Washington, Sep 11 (IANS) US President Barack Obama Saturday called for "heightened state of vigilance and preparedness" as the country commemorates the 10th anniversary of the Sep 11 terrorist attacks, Xinhua reported.

Obama made the remarks during a meeting Saturday morning with his national security team "to review ongoing efforts to mitigate potential terrorist threats as well as to review steps taken to enhance the nation's security posture leading into the 9/11 anniversary," the White House said in a statement late Saturday.

The meeting was attended by Secretary of Homeland Security Janet Napolitano, National Security Advisor Tom Donilon, Assistant to the President for Homeland Security and Counterterrorism John Brennan, Director of the Central Intelligence Agency David Petraeus, Director of the Federal Bureau of Investigation Robert Mueller and other senior officials.

The US is now on high alert triggered by a "specific, credible but unconfirmed" terror threat surrounding the 9/11 anniversary.

The threat was first revealed Thursday by US officials that at least three individuals planned to launch a vehicle-borne attack against Washington D.C. or New York around the anniversary.

"He (Obama) directed his team to pursue vigorously all threat information and to ensure a heightened state of vigilance and preparedness as we commemorate the anniversary of the 9/11 attacks, " the statement said.

Despite of the threat, Obama did not change his schedule to participate in a variety of commemorative events in New York city, the Pentagon and Shanksville, Pennsylvania, which were at the centre of the terrorist attacks a decade ago, with nearly 3,000 people killed.

This was the first "credible piece of information we've gotten" surrounding the 9/11 anniversary, US Vice President Joe Biden said Friday.