No US entry by terrorists, sources say

There is no evidence that anyone associated with al-Qaida has entered the United States to attack on the 10th anniversary of Sept 11, said senior U.S. officials.

However, since Wednesday, police and FBI have been on alert while investigating a "credible terror threat." The plot involves detonating a car bomb in bridges or on tunnels either in Washington DC or New York City, reports the Houston Chronicle.

Intelligence officials are chasing a tip from a CIA informant abroad who said that men have been ordered by al-Qaida's new leader Ayman al-Zawahiri to attack on the tenth anniversary of Sept 11, reports CBS news. The informant has been reliable in the past.

Secretary of State Hillary Clinton said that the threat was being taken seriously.
"We learned from the raid on bin Laden's headquarters and going through all of the material that al Qaeda was still determined to attack around anniversaries."

However, two of the three men involved in the terror threat could be U.S. citizens, reports the New York Times.

Vice President Joe Biden confirmed the credibility of the threat, reports CBS news.

In New York City, local police forces are cracking down, reports Bloomberg:

“We have already had a full complement of people working shifts because of the Sept. 11 anniversary prior to this,” Jim Margolin, a spokesman for the Federal Bureau of Investigation’s New York office, said yesterday. “We are taking the logical investigative measures to assess this threat.”

New York police officers will extend their shifts by four hours at least through Sept. 12, said New York Police Commissioner Ray Kelly. Officers will increase vehicle checks and monitoring of bridges and tunnels, Kelly said. Police will also perform more baggage screenings in subways, patrol outside places of worship and government buildings and conduct bomb sweeps of public garages.

“We will deploy quick-reaction teams consisting of heavily armored officers,” Kelly said.

As of Saturday, there has been no intelligence to back up the tip, and officials, speaking on the condition of anonymity, are questioning its credibility, reports the Houston Chronicle.