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 probes 9/11 anniversary terror threat
