WASHINGTON (Reuters) - The United States should consider using air strikes, such as attacks by unmanned drones, to battle militants in Yemen that threaten American security, a senior U.S. senator said on Wednesday.

Sen. Carl Levin said that air strikes, clandestine actions, and stepping up U.S. military aid to Yemen are among options that should be considered for dealing with the threat from al Qaeda militants in the Gulf Arab state.

U.S. officials say the Nigerian man accused of trying to blow up a Detroit-bond airliner on December 25 received al Qaeda training in Yemen.

Levin, a Democrat, is chairman of the Senate Armed Services Committee, making him one of Congress’ most influential voices on military matters.

“I think that these are proven threats to the United States, and if we identify them, it’s appropriate for us to act against them,” Levin said in a conference call with reporters. He said “most options ought to be on the table,” but not a U.S. invasion of Yemen.

President Obama has said the United States does not plan to send U.S. troops into Yemen or Somalia as those countries struggle to contain Islamist militants.

The CIA under Obama has expanded attacks using unmanned aerial drones against al Qaeda and Taliban targets along the Afghanistan-Pakistan border.

Levin said any air strikes in Yemen would need to be done with either the support or the acquiescence of Yemen’s government. He spoke by phone from Dubai, where he had stopped on the way home from a trip to Afghanistan.