NEW YORK -- A newly revealed terror threat against the city is credible but not corroborated, Mayor Michael Bloomberg said Thursday.
Bloomberg, speaking at police headquarters, said the New York Police Department is deploying additional resources around city to keep residents safe ahead of the 10th anniversary of the Sept. 11 terror attacks on Sunday.
"We take all threat reporting very seriously," he said. "We continue to ask the public to remain vigilant as we head into the weekend."
U.S. officials said Thursday they were investigating a detailed al-Qaida car bomb plot aimed at bridges or tunnels in New York or Washington.
NYPD Commissioner Raymond Kelly said he's increasing patrols and the towing of illegally parked cars. He said there will be more bomb-sniffing dogs on the streets and an increased focus on bridges, tunnels and other infrastructure.
Information gleaned from Osama bin Laden's compound in Pakistan in May indicated al-Qaida had considered attacking the United States on the 10th anniversary of the Sept. 11 attacks and other important dates.
NBC News is reporting that a plan originating out of Pakistan includes the use of truck bombs on or near the anniversary, possibly focusing on bridges or infrastructure.
Both New York and D.C. leaders say ceremonies will go on as planned for this weekend.
Security has been enhanced around the country ahead of Sunday's anniversary.