Federal officials plan to deport four men arrested on immigration charges as part of an investigation into an uncorroborated terrorist threat that closed a Baltimore harbor tunnel for nearly two hours Tuesday, immigration officials said yesterday.

Ernestine Fobbs, a spokeswoman for the U.S. Immigration and Customs Enforcement agency, said all four had deportation orders for various immigration violations before they were detained and had failed to appear for deportation hearings.

The FBI, meanwhile, reiterating that the threat remained uncorroborated and of undetermined credibility, continued to investigate. Barry Maddox, a spokesman with the FBI's Baltimore field office, said that the Baltimore FBI's Joint Terrorism Task Force is heading the probe.

"It's continuing," he said. "Leads are being followed up."

Authorities closed the Harbor Tunnel on Interstate 95 for more than 90 minutes and searched vehicles at the Fort McHenry Tunnel on I-95 after receiving a warning from an informant in the Netherlands that terrorists planned to detonate explosives in one of the tunnels.

But a high-ranking federal law enforcement source with knowledge of the case said yesterday evening that the four men had no connection to the informant. Another federal law enforcement source said the source of the warning had failed a lie detector test. The sources spoke on the condition that their names not be used because the investigation is ongoing.

The decision by authorities to close the tunnel was linked to raids that were carried out Tuesday in Baltimore, the second source said. Investigators sought several men who, according to the informant, would drive vehicles filled with explosives through a Baltimore-area tunnel. The source said local authorities took action at the tunnels about the time of the raids on the chance that, if the threat was real, the raids would force the bombers' hand.

The men facing deportation are Mohamed Ahmed Mohamady Ismail, 30, Mohamed Mohamed-Abdelhamed Elsyid, 48, and Suied Muhamad-Ahamad, 28, all of Egypt; and Ahmad Al Momani, 58, of Jordan.

FBI agent Richard Kolko said authorities hope the investigation will be completed within days.

Staff writers Sari Horwitz and Dan Eggen contributed to this report.

Police search vehicles at the entrance to the Fort McHenry Tunnel in Baltimore on Tuesday. Authorities were responding to an uncorroborated warning of a terrorist threat.