This article was reported and written by Judith Miller, Benjamin Weiser and Ralph Blumenthal.

he airborne assault on the World Trade Center and the Pentagon is the culmination of a decade-long holy war against the United States that is escalating methodically in ambition, planning and execution.

At the same time, the trail of terror ?much of it, officials say, either directly organized or inspired by Osama bin Laden ?shows a remarkable coherence in structure and operations that is frustrating government efforts to extinguish the threat.

"This is the same old war that came to a new battlefield," said James K. Kallstrom, the former director of the Federal Bureau of Investigation office in New York, who oversaw major terrorism investigations in the 1990's.

The hallmarks of that old war are now being scrutinized by investigators with new urgency. They include the recruitment of willing martyrs and their indoctrination and training, the planting of agents in target countries years in advance, the preparation of false identity documents, the provision of money and credit, and the creation of a compartmentalized structure for security.

Above all, officials say, the new holy warriors are persistent. They learn from failure. And they revisit targets until their mission is accomplished.

Much current anxiety centers on whether this round of terror is over. One ominous pattern is the "one-two punch" that the jihad network strives to deliver. The plotters of the World Trade Center bombing in 1993 intended to follow one devastating attack with another on other New York landmarks. And Middle Eastern intelligence officials say that a foiled bin-Laden conspiracy to destroy hotels and holy sites in Jordan at the millennium was to have been followed by a second wave of explosions.

Beyond that, administration officials who most closely monitor Mr. bin Laden's activities warn that the next round of terror could even involve weapons of mass destruction. Satellite pictures of dead animals on test ranges show that militants have been experimenting with various poisons at a terrorist training camp that Mr. bin Laden runs in eastern Afghanistan.

His group tried to buy chemical weapons and nuclear components in the mid-1990's, according to testimony in the embassy bombings trial earlier this year.

The evolution of guerrilla tactics coupled with an elusive infrastructure have repeatedly stymied campaigns by successive administrations to eradicate such terrorism. But the latest attacks have convinced American policy makers that they must now destroy the infrastructure as well as the terrorists themselves.

While the terrorists have shifted from bombs on the ground to airstrikes, their methods appear largely unchanged. Most have evolved from the training provided by Mr. bin Laden's network of nearly a dozen camps in Afghanistan which have produced the foot soldiers for every terrorist strike prosecuted in New York since the first World Trade Center attack in 1993.

In last week's attacks, for example, investigators said the terrorists relied on small cells of four or five people to hijack planes and crash them into crowded targets. As they have done before, the cells appear to have received support from a larger network on the ground in the United States and elsewhere.

That use of such cells is characteristic, testimony showed in the recently concluded embassy bombings trial in New York. And the choice of the World Trade Center as a target could almost have come off the pages of a terrorist training manual that prosecutors introduced earlier this year in that trial.

On Page 12, under "missions required," a little-noticed section of the manual lists "blasting and destroying" embassies and "attacking vital economic centers."

One of Mr. bin Laden's top aides has also written that small cells help ensure the safety and secrecy of operations. Agents communicate through the use of "dead drops" like spies, and each has discreet, designated responsibilities. These include conducting surveillance of targets, planning an operation and carrying out an actual attack.

On Thursday, Attorney General John Ashcroft characterized the attacks as "orchestrated, coordinated assaults" that were "conducted in a technically proficient way."

Officials said this week that the World Trade Center attacks may have been carried out by Mr. bin Laden working closely with other terrorist groups. But counterterrorism officials have long maintained that Mr. bin Laden's organization actually embraces like-minded militant Muslim groups, notably the Egyptian Islamic Jihad, which helped assassinate President Anwar el-Sadat in 1981.

Officials said that some of the hijackers identified by the F.B.I. this week had lived in the United States for years. That also fits the pattern. One of Mr. bin Laden's former top aides told the F.B.I. in 1997 that Mr. bin Laden had planted hundreds of terrorists, known as "sleepers" or "submarines," who would lie low for years until they were activated.

The aide, Ali A. Mohamed, a former American Army sergeant who pleaded guilty to terrorism charges last year, also said that the United States was hampered in its efforts to stop terrorism because the profiles it uses to identify potential terrorists are flawed.

"Mohamed implied that trained terrorists don't order their people to blow things up," an F.B.I. document says. "Terrorists are trained and then they act."

One characteristic of a bin Laden operation is advance surveillance and meticulous preparation. In case after case, according to United States court documents and interviews with intelligence officials, Mr. bin Laden's followers have devoted months, even years, to laying the groundwork for their attacks.

Ali Mohamed said that the planning for the 1998 bombing of the American Embassy in Kenya, which killed 213 people and wounded thousands, had begun five years earlier, when he first went to Nairobi for Mr. bin Laden in 1993 to scout out potential bomb targets, including the American Embassy.

Middle Eastern intelligence officials have also said that in preparing to strike the embassy in Nairobi, militants in one of Mr. bin Laden's Afghan camps constructed a wooden model built to the scale of the embassy building to study how to attack it.

The millennium bombing plot to blow up tourist and holy sites in Jordan dates back to May 1998, according to Jordanian prosecutors. One of the plotters spent more than a year using a forged gold dealers' license to buy sulfuric acid and 5,200 pounds of nitric acid in quantities small enough to escape attention.

In the latest attack, hijackers who took over American Airlines Flight 11 from Boston were said to have repeatedly cased the airport before the hijacking, according to published accounts. One of the hijackers spent four years in pilot school in Florida learning how to fly airplanes. He was one of those who the F.B.I. said helped commandeer that plane and crash it into the first twin tower.

"The evidence indicates," Mr. Ashcroft said on Thursday, "that flight training was received in the United States and that their capacity to operate the aircraft was substantial."

Jihad operatives have long favored symbolic targets. In addition to the first strike on the World Trade Center in 1993, there was a failed plot later that year involving more than a dozen conspirators to blow up the United Nations, the Lincoln and Holland Tunnels, and the Federal Building in Lower Manhattan, which houses the F.B.I. In the millennium plot, recent testimony has shown, Los Angeles International Airport was one of the group's targets.

The use of jets recalls the aborted 1994 conspiracy led by Ramzi Ahmed Yousef to blow up as many as a dozen American jumbo jets as they flew over the Pacific. Mr. Yousef, who stayed in one of Mr. bin Laden's guest houses in Pakistan, and was convicted in the 1993 bombing of the World Trade Center, later lamented to F.B.I. agents that he had lacked the money and explosives to bring down the twin towers.

Several members of Mr. bin Laden's group, Al Qaeda, have been pilots. Before joining Mr. bin Laden, Ali Mohamed had worked briefly as a security adviser for Egypt Air. And another, Ihab M. Ali, an Egyptian who drove a taxi in Orlando, Fla., underwent flight training in Norman, Okla.

Ihab Ali's "pilot training and international travels concerned efforts to assist in Al Qaeda's terrorist activities," federal prosecutors charged in an indictment last year.

Mr. bin Laden's form of terrorism is a study in persistence. In January 2000, officials say, his terrorists failed to blow up the Navy destroyer Sullivan in Yemen because their overloaded dinghy filled with explosives sank as they launched it toward the American ship. Ten months later, the same group used a sturdier boat to attack the destroyer Cole, killing 17 sailors.

It also transcends geographic, religious, and ideological boundaries. In the current investigation, officials suspect that the conspirators come from several terrorist groups based in different countries who were working together. Historically, Mr. bin Laden has forged alliances with a cross section of jihad groups, some of which were traditional rivals, like Egypt's Islamic Group and the Egyptian Islamic Jihad.

In an indictment, the government has said that Al Qaeda acted as an umbrella organization for jihad groups in Egypt, Saudi Arabia, Yemen, Somalia, Eritrea, Djibouti, Afghanistan, Pakistan, Bosnia, Croatia, Albania, Algeria, Tunisia, Lebanon, the Philippines, Tajikistan, Azerbaijan, Chechnya and Kashmir.

The government has also said that there was a "working agreement" among Mr. bin Laden, Iran and the National Islamic Front of Sudan to "work together against the United States, Israel and the West." The American roots of Mr. bin Laden's jihad, officials say, lie in part in a now-defunct Islamic office on Atlantic Avenue in Brooklyn ?the Alkifah Refugee Center, which served as a recruiting station for the Afghan war against the Soviet Union. Even before the Soviets withdrew from Kabul in 1989, Mr. bin Laden had begun expanding his holy war to other parts of the world, including the United States.

It was the 1993 arrest of Omar Abdel Rahman, the charismatic, blind Egyptian sheik in the plot to blow up New York landmarks, that partly inspired Mr. bin Laden's rage toward the United States, the government has said.

As in previous attacks, Mr. bin Laden also appears to have recruited a group of operatives all but unknown to American intelligence. While investigators have not said whether they had previously tracked any of the 19 suspects the F.B.I identified on Friday, no one has been able to tie them to previous incidents.

Steven Emerson, a terrorism expert who has called for a crackdown on terrorist networks in this country, said that none of the names had come up in his extensive research on many of the 5,000 militants who have received training in Mr. bin Laden's camps. "That is not surprising," Mr. Emerson said. "These people are the cannon fodder."

Counterterrorism officials have worried about the challenges of the new battlefield for years. "It's not like the old Mafia-type cases," said one senior F.B.I. official in a speech in 1997, "where you pigeonhole somebody and you say he's a member of this group.

"You tend to figure out who they may be associated with, and all of a sudden they're talking to all of the different groups at a conference where they are all bound again by the jihad, by their religious beliefs and extremism.

"And almost all of the groups today, if they chose to, have the ability to strike us here in the United States. They're working toward that infrastructure."

The official who made those comments, John P. O'Neill, who oversaw the F.B.I.'s investigation into Mr. bin Laden, retired last month to become director of security for the World Trade Center. After the first plane rammed the trade center last week, he called a close friend to say that he was on the street and was all right.

He has not been heard from since.