NEW YORK (AP) An Algerian living in Brooklyn who prosecutors say planned to assist another Algerian caught smuggling explosives into the United States was held without bail today after a court appearance.

Abdel Ghani shook his head as Assistant U.S. Attorney David Kelley portrayed him as eager to assist Ahmed Ressam, arrested Dec. 14 on charges he smuggled explosives from Canada to the United States.

Ghani's arrest during an early morning raid on his apartment Thursday came as law enforcement officials questioned and detained dozens of people in major cities from New York to San Francisco, mostly on immigration charges.

The effort was part of an increased vigilance against possible beds of terrorism with the approach of the new year and left authorities even more confident that no credible security threats loomed.

No plea was entered during Ghani's appearance before U.S. Magistrate Ronald L. Ellis in Manhattan. Kelley said Ghani, 31, was in the country illegally. Ghani's lawyer, Roland Thau, said it was pointless to argue for bail since the government was alleging his client had few ties to the community.

''I try not to do futile things,'' he said outside court.

Moments earlier, Thau had asked Ellis to toss the case out on the grounds that none of the alleged crimes occurred in the jurisdiction of U.S. District Court in Manhattan and because the government had not sufficiently supported the charges.

Kelley said the government could properly bring charges against Ghani in Manhattan because the defendant had ridden in a plane over an area including the court's jurisdiction on his way to Seattle two weeks ago to try to meet with Ressam.

Ellis conceded that the question of jurisdiction was a ''close issue'' but agreed to give the government the benefit of the doubt for now.

Ghani was charged in a criminal complaint with concealing his support for Ressam's efforts to violate federal explosives laws and with conspiring with others to use fraudulent credit and bank cards.

The complaint alleged that Ghani had traveled to Seattle under an assumed name to meet Ressam, planning to raise money with him in Chicago.

The FBI said a confidential source told authorities that Ressam had been tasked by an unidentified group ''to take the explosive-laden vehicle to a parking lot and walk away from it'' and that someone else would retrieve it.

On December 25, Ghani indicated to an associate that he didn't know Ressam would be in possession of explosives, and said he was upset by it. However, the complaint alleges, Ghani said he ''would have been with Ressam to the end had he known'' Ressam's plans.

He also mentioned ''that the situation was boiling in Algeria and that the United States and the CIA are running everything over there.'' Algeria has been locked in a bloody civil war for nearly eight years.

The associate told the FBI that Ghani had conversed with another person recently, agreeing that ''Allah will shake up this world, that a new generation will punish America and that Islam's renaissance will rise from Algeria,'' the complaint said.

The raid and the sweep by authorities nationwide came just weeks after Ressam was arrested in Port Angeles, Wash., on explosives smuggling charges. Even after interviewing detainees, officials stressed they hadn't turned up information suggesting a terrorist attack was imminent on any U.S. city.

''We did interview people in our area with regard to information they may have about persons involved in terrorist activities,'' FBI spokeswoman Marjorie Poche said in Dallas. ''We don't have any specific information on anything directed here.''

The nationwide questioning occurred as prosecutors in Vermont for the first time drew a connection between Ressam and a Canadian woman detained after trying to cross a remote border in Vermont.

The prosecutors said the two were linked to an Algerian militant organization. The argument persuaded a federal magistrate to continue to hold the woman, Lucia Garofalo, without bail.

Law enforcement officials said some of those being questioned in the United States were of Algerian descent. Most of the interviews were uneventful, although agents in Boston ended up in a chase after one Algerian man fled.

After being questioned, five men were arrested by federal agents in Boston, most of them Algerian. One was charged with illegal entry, another with possession of a false green card while three others were detained on civil charges related to their immigration status.

In New York City, authorities detained an Algerian man on immigration charges. He was identified as Najmeddine Houaichi.

Officials in several cities said their questioning was aimed at turning up new leads.

''It is just people we believe may have information that may help us in our investigations,'' said Ramiro Escudero, an FBI spokesman in Los Angeles. ''It does not mean they are involved in any terrorist activities.''

Earlier Thursday, FBI Director Louis Freeh met with top Canadian and intelligence officials to ensure continued coordination on law enforcement and intelligence matters.

''While no specific development prompted today's meeting, these continuing high level discussions reflect the importance both countries place on seamless law enforcement and intelligence efforts relating to Y2K and terrorism issues,'' the FBI said in a statement.

In court documents, prosecutors said Ms. Garofalo and Ressam were both linked to the Armed Islamic Group, which is known by its French initials, GIA.

The GIA is an extremist faction held responsible for some of the bloodiest attacks in Algeria's civil war. It has also been blamed for bombings in France in 1995 and 1996 and an airplane hijacking in 1994.

Ressam faces charges of trying to smuggle RDX, a powerful demolition explosive, and timing devices into Washington from Canada.