No New Bomb Arrests Imminent, Officials Say : Probe: Authorities are still uncertain if trade center explosion was work of international terrorists. Expert is scheduled to be lowered into blast site.

NEW YORK —  Three days after the capture of Mohammed A. Salameh, the prime suspect in the World Trade Center bombing, no new arrests are considered imminent and authorities have not determined whether the explosion was an act of terrorism directed from abroad, the FBI official heading the investigation said Sunday.

“I don’t see any more arrests at this time,” said James M. Fox, an assistant FBI director who heads the New York field office. But Fox also noted that last week’s dramatic breakthrough “came without warning.”

Another source familiar with the investigation said the probe has hit “a plateau” but that more progress is expected when officials finish processing the huge amount of technical information now being collected and interview a number of Salameh’s associates, whom they are still seeking.

Many leads are being pursued overseas, he said, apparently by the FBI legal attaches who are based in the embassies of many foreign countries.

The source said authorities are optimistic that they can determine by the end of the week whether the bombing was a foreign-directed terrorist attack or the work of local militants.

Fox and other top FBI officials huddled Sunday with representatives of the federal Bureau of Alcohol, Tobacco and Firearms, the New York City Police Department and other agencies.

When they emerged, their comments focused more on the questions that remain unanswered since a powerful bomb, allegedly loaded into a van that had been rented by Salameh, exploded in the trade center’s underground parking garage, killing five people and injuring approximately 1,000 others.

Fox said in an interview that the reason for the attack is still unknown. With Salameh’s arrest last Thursday, “there’s been a lot of speculation,” he said. “But I’d have to say we are not closer to a motive. I can’t say we are moving in one direction or the other.”

He declined to say whether firm links have been found between a second man taken into custody, Ibrahim A. Elgabrowny, and the bombing. Other sources indicated that there is no hard evidence against him yet. Elgabrowny, an associate of Salameh and a relative of the accused assassin of Rabbi Meir Kahane, a right-wing Jewish leader, was arrested for allegedly interfering with a search conducted in the bombing case.

The origin of the bomb plot and those involved is a matter of particular sensitivity to the U.S. foreign policy community, and the Clinton Administration and foreign governments are waiting with anticipation for definitive information.

“I think it is too early to reach conclusions or speculate,” Samuel (Sandy) Berger, deputy national security adviser, said in a Cable News Network interview. “I think the first and urgent responsibility here is to get the facts. Once we get the facts, once we know what the address of this incident is, I can assure you that we will take action.”

Investigators hope they can move into higher gear after a bomb expert is gingerly lowered today to the actual site of the explosion, located deep inside a five-story-tall, rubble-strewn crater beneath the remains of the trade center’s garage.

Bomb chemists hope to compare samples taken at the seat of the explosion with bomb-making ingredients seized from a storage shed rented by Salameh and from an apartment in Jersey City, N.J., once occupied by an associate of the suspect. If the explosives are the same, the still-circumstantial case against Salameh would be strengthened immensely.

Perhaps even more significant, they hope to find enough fragments of the bomb’s detonator or timing device to provide a connection to previous bombings or to terrorist groups.

The theory that some conspirators, including the van’s driver, could have perished in the gigantic explosion has not been discounted.

“That’s one of the secrets we will discover when we get into the pit,” Fox said.

Investigators are hopeful of finding clues that could trigger more searches for evidence.

“I don’t think all search warrants have been returned, but we are 90% complete,” Fox said. “There could be more searches in the next few days.”

Since Salameh’s arrest, members of a police and interagency anti-terrorist task force have compiled a list of Salameh’s roommates and associates, some of whom have not been seen since the bombing.

Federal agents are seeking to question a man authorities describe as a “Jordanian associate” of Salameh who was with him on Feb. 23 when he rented the van believed to have been used in the bombing.

Fox acknowledged that agents so far have been unable to disprove Salameh’s claim that the van was stolen from him the night before the blast.

On Sunday, FBI agents returned for about 30 minutes to a Jersey City apartment where they had found bomb-making parts.

A man who said he was the owner of the small second-floor apartment was busy repainting it and told a Times reporter that the agents confiscated the trash left by the previous occupants, who had moved a week ago.

He said two men had lived in the unit since early January but that he did not know their names. He said he rented the partment for $500 a month plus a $500 deposit after they responded to a newspaper ad he had placed. He and that he did not ask the men for background information or to sign a lease because they did not speak English.

“When they left, they told me they were canceling the lease because they had found other jobs in Brooklyn,” he said.

The man, who declined to give his name, said he had the impression from FBI agents that they were looking for more than just the two men. He said the former tenants did not match the description of the suspects seized so far in connection with the bombing.

Residents of the building where Salameh is believed to have lived in Jersey City just before his arrest said that the suspect and a group of friends on several occasions carried a man with both legs missing from the knees down into the apartment. The man, they said, appeared to be in his 40s and was a previous occupant of the apartment. The residents said they did not know the man’s name.

Muslim leaders complained Sunday that “illiterate Americans” have been making abusive phone calls to mosques, Muslim organizations and the homes of Muslims across the country since the arrest of Salameh, a Muslim born in the Israeli-occupied West Bank. A third-story window of the Jersey City mosque where Salameh worshiped was broken.

“It’s worse than during the Gulf War,” saiT. Mehdi, president of the New York-based American-Arab Relations Committee and the secretary-general of the National Council on Islamic Affairs. He said some Americans are angrier at Muslims now than during the Persian Gulf War because the violence is taking place close to home.

Reports Sunday from the Mideast began to sketch a somewhat fuller portrait of Salameh.

In an interview in Zarqa, Jordan, with the Associated Press, Salameh’s mother, Aysha, said that her son traveled to the United States on Feb. 17, 1988, to pursue a master’s degree in business administration.

“He had big dreams. He wanted to fulfill his dreams in America. He is not a terrorist,” she said. She said she is sure “of America’s fair justice, and that my son will come out of this nightmare soon.”

Salameh’s father, Amin, is a retired officer in the Jordanian army. Salameh’s mother said her son loved Western movies, wrestling and soccer when he was growing up.

A brother, Ahmed, said Salameh was not a Muslim fundamentalist but became engrossed in Islamic teachings in his final years in high school and began praying and reading the Koran with friends. Authorities in Jordan said that Salameh and his family do not have criminal records.

In New York, Salameh’s defense lawyer said the 25-year-old man did some construction work. Neighbors in Jersey City said he hung around with taxi and truck drivers.

Meanwhile, Mayor David N. Dinkins said he was “concerned” that the New York-New Jersey Port Authority, which operates the World Trade Center, had rejected security recommendations made six years ago by an anti-terrorist task force it had set up.

The task force cited concerns about the vulnerability of the trade center’s garage, a source said.

Times staff writers Ronald J. Ostrow, Gebe Martinez, Elizabeth Shogren and William C. Rempel contributed to this story.