FBI agents yesterday arrested Nidal A. Ayyad of Maplewood, N.J., in connection with the bombing of the World Trade Center in New York and said the Kuwaiti-born chemical engineer had close ties to Mohammed A. Salameh, the Jersey City man arrested last week in the investigation.

Both are charged with aiding and abetting in the underground explosion Feb. 26 when five people were killed and more than 1,000 injured.

In a complaint filed in U.S. District Court in Newark, FBI officials said Salameh had made repeated telephone calls to Ayyad from outside a rented storage shed containing chemicals that officials said could be used to fashion an explosive device.

The complaint also said Salameh had Ayyad's business card, that Ayyad rented a red sedan believed to have been driven to rent the van known to have been used in the bombing and that the two shared a bank account.

Ayyad, 26, who immigrated from Kuwait in 1985 and became a naturalized citizen two years ago, is a 1991 chemical engineering graduate of Rutgers University in New Brunswick, N.J. He was employed as a process engineer at AlliedSignal Inc. in Morristown, N.J., authorities said. Bail is to be set at a hearing in Newark Friday.

No further details were released about the extent of ties between Salameh, 25, and Ayyad or what FBI officials believe Ayyad's role in the bombing may have been. But James Esposito, special agent in charge of the FBI's Newark office, placed special emphasis on Ayyad's training as a chemical engineer.

"By his educational background, he has certain expertise that lends itself to making explosives," Esposito said.

Sources close to the investigation also said the relatively conspicuous paper trail linking Salameh and Ayyad suggests that the bombing was the work of a relatively unsophisticated group of Middle Eastern immigrants based in the metropolitan New York area and not the harbinger of a wave of state-sponsored terrorism washing over the United States.

"We don't have direct, concrete ties to a group here or abroad," said James M. Fox, head of the FBI's New York office. Fox repeatedly has discounted published speculation about involvement by radical Muslim cleric Sheik Omar Abdul Rahman, who preaches at a Jersey City mosque that Salameh attended.

"We aren't looking for the sheik and don't particularly want to interview him at this time," Fox said yesterday.

Authorities said Ayyad was arrested by FBI agents at 6:42 a.m. in Maplewood, 15 miles from Manhattan where he lived in an apartment with at least two other people. At a brief arraignment, the tall, dark-haired Ayyad wore glasses and said nothing beyond confirming that he understood English.

Several members of Ayyad's family, including two brothers, his parents and pregnant wife, attended the hearing. His father, Abdel-Rahman Joseph Ayyad, who had to be taken from the room after collapsing, said his son knew Salameh but was not guilty of wrongdoing. Resiq Ayyad, 17, said his brother was guilty of "nothing but being friends with Salameh."

Ayyad's brother, Abdul, 14, said their family is of Palestinian origin and came to New York from Kuwait in 1985.

The connection between Salameh and Ayyad appears to have been made initially in testimony of witnesses interviewed by the FBI at the truck-rental agency in Jersey City where Salameh obtained the vehicle allegedly used to carry the trade center bomb. Witnesses said Salameh came to the agency with another man, using a red General Motors sedan described as "looking like a rental vehicle."

In checking records at a National Car Rental agency, FBI agents said, they found that, on Feb. 15, Ayyad had rented a red Oldsmobile with an additional driver listed as "Salameh."

Another connection was made last Friday after police discovered a rented storage shed in Jersey City that contained chemicals and material that could be used to make explosives. Authorities said witnesses reported seeing Salameh using a pay phone outside the shed. The complaint said that, on the day before the bombing, records show that four calls were made to Ayyad's office at AlliedSignal Inc.

AlliedSignal Inc. is an international manufacturer of engineered materials and automotive and aerospace products. Company officials said that Ayyad was being suspended without pay and that he has worked since 1991 as a process engineer in the company's development laboratories in Morris Township.

Fox would not comment on whether more arrests were likely this week, but investigators appeared to be seeking several other people thought to be affiliated with Salameh and Ayyad. Witnesses have said, for example, that several men were seen entering and leaving the rental shed containing the chemicals.

Esposito also said the bank account shared by the two men contained several other names, but he did not elaborate.

The complaint against Ayyad also contains new information about the storage shed discovered and searched by federal agents last Friday.

Inside, it said, agents found all of the ingredients needed to fashion an improvised high-explosive device -- "several 100-pound bags labeled Urea, numerous bottles labeled nitric acid, one plastic container labeled sulfuric acid, numerous other chemicals and compounds, a pyrotechnic fuse, tubing, graduated cylinders, flasks, beakers, filter paper, funnels, a mortar and pestle and stirring rods."

Federal experts have concluded that, if 1,000 to 1,500 pounds of the chemicals found in the shed were combined with a small explosive charge, the resulting blast would be similar to the one that rocked the trade center, according to a law enforcement official familiar with the investigation.

The complaint cited the opinion of a federal bomb analyst who said the "chemicals and compounds" found in the storage shed "can be combined to produce a primary high explosive."

Jeffery L. Rankin, who is assistant dean of engineering at Rutgers and taught Ayyad in two courses, said he was a "very typical, common student" who "did well on all the exams."

Rankin said the principles of chemical engineering taught in Ayyad's classes "could be applied" to making a bomb.

"These chemical engineers take chemical reaction and reactor design," he said. "The principles of explosives were only half an hour to an hour of the class. He could have picked up principles here, principles there, and a student of his competence, experience with material, could have put them all together."

After graduating from Rutgers, Ayyad took what Rankin described as "a very common entry-level position" with AlliedSignal.

Meanwhile, Ibrahim Elgabrowny, also arrested last week in the bombing investigation, met with new attorneys to plan a strategy that they hope will lead to his release on bail at a hearing this afternoon.

The Egyptian-born Elgabrowny, 42, was arrested for assaulting two federal agents trying to search his apartment. Prosecutors have not disclosed what role he may have played.

Elgabrowny has ties to Salameh and is a cousin of Sayyid Nosair, convicted of assault and weapons charges in the shooting death of militant Rabbi Meir Kahane in 1990. He was tried but acquitted of murder in the case.

Gladwell and special correspondent Rachel E. Stassen-Berger reported from New York.