As tomorrow’s anniversary of the September 11th attacks approaches, police officials say there is renewed interest in three vans that have been stolen in and around the city since the end of August that could be used in a possible car bombing plot, though no specific link to a terrorist threat has been made.

A white Econoline van was stolen from a Jersey City storage facility on August 21.

Two green vans were also stolen early this month from Tully Construction in Queens. The company did recovery work at the World Trade Center site.

The thefts have not been specifically connected to a plot, but officials from the police department say they are being extra careful.

Counterterrorism officials tell reporters at least two of the three men they are looking for could be U.S. citizens or have U.S. travel documents, and their primary mission is to detonate a car bomb in either New York or Washington, or at least cause as much destruction as they can.

A CIA informant told intelligence officials the men had been ordered by new al-Qaida leader Ayman al-Zawahiri to mark the 10th anniversary with an attack.

The tipster said the would-be attackers are of Arab descent and may speak Arabic as well as English.

The New York Times reports the men may have traveled from Afghanistan and that one may have the common Arabic name “Suleiman,” but it is unclear whether that is his given name or an assumed name.

So far, investigators have been unable to corroborate the threat.

The news comes as the city has been tightening security to prepare for tomorrow’s anniversary of its worst terrorist attacks.

Major transit hubs, bridges, tunnels, landmarks and houses of worship are all seeing an increased police presence.

“Transportation, especially rail transportation, is the number one target of terrorists. In the last 10 years we’ve seen over 200 targets. We saw Madrid, we saw Moscow, we saw London,” said security expert Nicholas Casale. “We know they want to attack our transportation systems. You can’t totally secure it. It’s not like an airline.”

The subways are an “open system,” meaning that if every rider was screened, like in airports, the transit system would cease to function. Instead, law enforcement are holding random searches.

New York City Police Department officials report that on Friday they received 43 calls of suspicious packages throughout the city, when normally they would only get about 15.

READ MORE: NY1