Canadian authorities have issued an arrest warrant for a 32-year-old man who stayed for several weeks in a foul-smelling Vancouver motel room with Ahmed Ressam just before Ressam's Dec. 14 arrest by U.S. Customs agents as he tried to enter Washington state by ferry with a carload of explosives components.

The Royal Canadian Mounted Police warned citizens not to try to apprehend Abdelmajed Dahoumane, who is wanted for possessing or making explosives. Managers of the Vancouver motel where the two men stayed said their room reeked with a rotten egg smell -- which could be consistent with law enforcement theories that the nitroglycerin in Ressam's car was a "home-brew."

New information also is emerging about the international connections of Ressam, 32, who is Algerian. Canadian officials said he has unspecified ties to the Armed Islamic Group or GIA, an Algerian organization that is blamed for the killings of hundreds of men, women and children there as part of the underground group's bloody struggle with the Algerian government.

As many as 150,000 people have been killed in the Algerian violence, some by terrorist groups such as the GIA and others by the Algerian security forces, which have waged a brutal war to suppress them. The fighting began in 1992, after Algerian officials canceled elections that Muslim fundamentalists were certain to win.

Canadian and French officials also have privately told reporters that Ressam received terrorist training in Afghanistan and Pakistan, and that he fought in Muslim military units in Bosnia against Croatian and Serbian militias. The GIA has reportedly dispatched a number of its fighters to take part in these missions, sometimes in coordination with Osama bin Laden, the millionaire Saudi who U.S. officials say masterminded the bombing of two American embassies in East Africa last year.

The Los Angeles Times quoted French government officials as saying that Ressam is suspected of involvement in the bombing of a Paris subway in 1996 that killed four and injured 91, as well as a series of brazen holdups near the city of Lille whose spoils were allegedly sent to Islamic radicals around the world.

Ressam once shared an apartment in Montreal with a member of the robbery gang, whom Canadian officials deported to Bosnia last year, law enforcement officials told The Washington Post.

The Globe and Mail reported in Toronto that Canada's spy agency tracked Ressam's activities for several years after he entered that country in 1994, but halted the investigation because counterterrorist officials lacked the personnel to continue.

"He has been known to us for some time," the newspaper quoted a senior officer of the Canadian Security Intelligence Service as saying. But "we had to drop it [the probe] recently because of a lack of resources. We just don't have the time and people to continue these investigations indefinitely." The CSIS official added that "this man is a professional."

Ressam had sought refugee status from Canadian authorities when he settled in Montreal in 1994. He said he had been tortured by Algerian security agents who accused him of being an arms dealer for the terrorists, an assertion he denied.

"To them, I was simply an Islamic terrorist, even though I had never been associated with Islamic movements," Ressam said in an immigration document filed in a Canadian court. "I spent a few hellish days in a jail cell. I was tortured with a rag doused with soap and bleach. . . . As a result of this suffering and injustice to an innocent man, I fear that the legal system is working against me. For that reason, I have decided to seek exile."

Ressam had entered Canada with a phony French passport, and at one point he failed to appear for a hearing that could have resulted in his expulsion from the country. A warrant was issued for his arrest, but he could not be found.

Two months ago, a team of French investigators flew to Montreal in an unsuccessful attempt to interview Ressam about his possible involvement in the 1996 bombing of a subway station in Paris, in which four people were killed, the Los Angeles Times said.

On Wednesday, Ressam pleaded not guilty to federal charges that he smuggled nitroglycerin and electronic timing devices into this country, and that he lied to U.S. Customs officials. He was arrested on Dec. 14 after he left a ferry that sails between British Columbia and Port Angeles, Wash., north of Seattle.

A number of Islamic organizations have sprung up in the United States and Europe in recent years to raise funds for the GIA and other Algerian rebel groups. A Canadian woman arrested while crossing the border into Vermont on Dec. 15 with another Algerian man is alleged to have vague connections to this network of groups.

U.S. prosecutors said in court documents that the car that Lucia Garofalo was driving and the cellular telephone that she carried were registered to Brahim Mahdi, who they say is a member of a terrorist-tied group called the Algerian Islamic League.

Mahdi has denied involvement in terrorist activity, as has a nuclear engineer in Switzerland who U.S. officials said founded the Algerian Islamic League and acted as an arms broker for the Algerian underground.

"I refute all these accusations down to the last detail," the MIT-trained nuclear engineer, Mourad Dhina, said in a statement, according to the Associated Press. "I declare in the most solemn manner that I know neither well nor distantly the people arrested over recent days in the United States and Canada."

Last week, Canadian investigators, carrying a search warrant and accompanied by bomb-sniffing dogs, raided an apartment in Montreal where Dahoumane had lived for two years, before his recent disappearance. They found no explosives.

The GIA, the extremist Islamic group with which Ressam is allegedly associated, has massacred entire Algerian villages that it believes collaborate with the authorities -- including women and children who have had their throats slit. The group has also killed dozens of foreigners and women who fail to wear veils.

Five years ago, the GIA staged the first of its few attacks outside Algeria. On Christmas Eve 1994, armed hijackers from the group seized an Air France jet in Algeria and killed several passengers. Planning to blow up the plane and its 170 surviving passengers over Paris, they rigged the aircraft with dynamite. But during a stopover in Marseilles, a French anti-terrorist team boarded the jet and killed the hijackers. The bomb attacks in French subways and commuter trains started a few months later.