US probes 9/11 anniversary terror threat

US officials warned of the threat of a terror strike on the United States reportedly involving bomb-laden trucks ahead of this weekend's 10th anniversary of the 9/11 attacks. "There is specific, credible but unconfirmed threat information," the Department of Homeland Security said in a statement on Thursday, as the White House confirmed President Barack Obama had ordered boosted counterterrorism efforts. "We have taken, and will continue to take all steps necessary to mitigate any threats that arise," the department added in a statement. US media said three individuals were reported to have entered the country in August and were allegedly seeking to carry out an attack using a vehicle laden with an explosive bomb. Although the country has already tightened security ahead of Sunday's anniversary, Obama had "directed the counterterrorism community to redouble its efforts in response to this credible but unconfirmed information," a White House official said. US media said possible targets were New York or Washington, as New York Mayor Michael Bloomberg announced a press briefing with the city's Police Commissioner Ray Kelly at 9:30 pm (0130 GMT) Thursday. New York Congressman Peter King, who heads the House Committee on Homeland Security, would not confirm any details after lawmakers were briefed about the situation. But he told CNN "there were very, very specific facts that were made known in this threat." "I can tell you that the administration, all levels of law enforcement, federal, state and local where it's appropriate are checking out every possible lead, running this to ground, and we've come a long way since September 11th." The United States is preparing to mark the anniversary of the devastating September 11, 2001 attacks in which almost 3,000 people were killed. Two hijacked planes hit New York's World Trade Center, collapsing the iconic twin towers, a third plane plowed into the Pentagon and a fourth crashed into a Pennsylvania field when passengers overcame the hijackers. US Navy commandos tracked down and killed Al-Qaeda Osama bin Laden at his hideout in the Pakistani garrison town of Abbottabad in May this year. During the raid, documents and computer files were seized at his compound showing his terror network had pondered strikes to coincide with the anniversary. "We continue to ask the American people to remain vigilant as we head into the weekend," the Department of Homeland Security said in its statement. The announcement came after the Pentagon on Wednesday raised the alert level at bases across the United States as "a prudent and precautionary measure," given Al-Qaeda's interest in milestones and anniversaries. Sunday's biggest event will be the reading of victims' names at Ground Zero, which will be attended by victims' family members, as well as Obama, former president George W. Bush, and Mayor Bloomberg. Although there have been no attacks on the scale of 9/11 in the United States in the 10 years since, the nation has been on heightened alert amid a series of foiled and failed attacks. Security is the main concern among organizers of the ceremonies remembering those who died and large crowds are expected as the country reflects on a decade of war abroad and fear of further attacks at home.