Frustrated police in New York City had to free a suspicious group of illegal Middle Eastern aliens because the Immigration and Naturalization Service "didn't want to be bothered" on the Memorial Day weekend. 

Not knowing whether the men they had nabbed were the hard-working immigrants they claimed to be or a terror gang plotting to wreak havoc, the local authorities had to let them walk in the end. 

The mystery men — some with phony IDs, and all admitted illegal immigrants — could have been held if agents from the INS had bothered to show up. 

"What's the point of stopping vans and risking your life when the one agency with power blows you off?" one angry lawman said. "And this is after Sept. 11." 

"It's frightening and disheartening," said another. "The agency that handles immigration didn't want to come down" — although every other law-enforcement agency did. "They didn't even want to be bothered." 

The INS didn't seem to have anybody on duty in New York City. The agency's contact number for the weekend rang at an office in Burlington, Vt., more than 300 miles away. 

"The [expletive] INS has one phone working Memorial Day weekend and it's in Vermont?" said another incredulous law-enforcement official. 

An INS spokesman said Wednesday, "Since Sept. 11, our primary focus has been on terrorist-related investigations and, contrary to belief, we are not in the business of detaining people without cause. These men posed no terrorist threat or, for that matter, any threat to the community." 

But the cops had no reason to think that when they confronted the men Friday. 

The case began about 4 p.m., when Bridges and Tunnels officers from New York's Metropolitan Transportation Authority police stopped a battered van from entering the Brooklyn-Battery Tunnel, which links lower Manhattan and Brooklyn, from the Manhattan side. 

The red-and-white 1990 cargo van had four Middle Eastern men jammed in front — one more than is legal. 

The commercial vehicle also bore only an address, 1006 Coney Island Ave., stenciled on its side, and not a business name, as required by city law. 

Officer Chris Lasalle opened the rear padlocked door and found three more men inside, a police report said. 

The seven men, most of whom were from Pakistan, produced a variety of paperwork, including a phony government card obtained in Times Square, a bogus passport, an identification card from Virginia, and some New York state nondriver IDs. 

They were taken to the officers' headquarters on the Brooklyn side of the tunnel, where detectives from the New York City Police Department Intelligence Division, the Joint Terrorist Task Force, the MTA, an assistant Brooklyn district attorney and interpreters had responded. 

The suspects said they worked for a construction company, Gill Waterproofing and Roofing in Brooklyn, to which the van was registered. 

At 6 p.m., the INS was called, but no agents responded. By 10 p.m. the Brooklyn district attorney's office, without INS intervention, had to release the four men who had what appeared to be legitimate IDs. 

At midnight, detectives again called, but were referred to a toll-free INS number that connected them with the Vermont office, where a concerned supervisor took information and said a Manhattan supervisor would be notified by morning. 

At 1 p.m., INS supervisor Frank Ciringione called, promising to provide instruction later, sources said. 

When asked if he wanted to talk to the prosecutor handling the case, he indicated he didn't — unless he had to. 

"They had a horrible attitude," one cop said of the INS. 

Three hours later, Ciringione called back and told ADA Jacqueline Kagan to free the other suspects, saying "INS would follow up at a future date in our own way." 

Ciringione declined to speak yesterday. 

Additional reporting by Brad Hunter and Eric Lenkowitz