The FBI has launched an intensive manhunt for several suspected Arab terrorists it says may have entered the United States illegally from Canada last week.

Officials are especially concerned that the men may be heading to the New York City area, based on information received from at least one intelligence source.

Because of the large gathering of Americans in New York City on New Year's Eve, authorities were taking the information seriously and pursuing the men even though there is no specific information that they are planning any activities, officials said.

The men, all of Arab ancestry, are believed to have arrived in the U.S. on or before Christmas Eve. Law enforcement officials said the five may have connections to others under watch in terrorism investigations.

The five men were identified on the FBI's Web site as:

• Abid Noraiz Ali, born Aug. 15, 1977.

• Iftikhar Khozmai Ali, born Sept. 20, 1981

• Mustafa Khan Owasi, born Nov. 12, 1969

• Adil Pervez, born Dec. 12, 1983

• Akbar Jamal, born Nov. 1, 1974

The FBI said it was possible that all five names and birth dates may be false.

An FBI spokesman told Fox News the men were considered "suspected terrorists."

In a written statement, NYPD Deputy Commissioner Michael O'Looney said:

"In response to the FBI bulletin, the New York City Police Department has increased its counter-terrorism efforts. The names and photographs of the five individuals cited in the bulletin are being disseminated to all police department commands."

New York Gov.George Pataki said there was "some reason to believe that [the men] came across the Canadian border into New York. We don't know where they are now."

"We want to know why they are here. We want to question them ... and find out more," White House spokesman Scott McClellan told reporters in Crawford, Texas, where President Bush was vacationing.

Officials said the men crossed the border from Canada together, but there was no specific information on what port of entry. They said it was possible that the men have split up since entering the U.S.

One official said U.S. authorities' interest in them was heightened when an intelligence source provided information that some of the men being sought were connected to others who are the subjects of terrorism investigations.

The intelligence information on the men came from an investigation into a worldwide smuggling operation that brings individuals with illegal passports into the United States.

The subjects of the manhunt are not those who ran the operation but likely are people who may have been smuggled across the border, Cogswell said.

The FBI said it was working with the Customs Service, the Immigration and Naturalization Service and the Transportation Security Administration to find the men.

INS spokesman Dan Kane said his agency has "implemented additional measures to look for these individuals."

The FBI asked anyone with any information pertaining to the five illegal immigrants to contact the nearest FBI office.

The Associated Press contributed to this report.