Republican presidential candidate and Texas Congressman Ron Paul is condemning the Obama administration for killing an American born al-Qaida operative Anwar al-Awlaki without a trial.

Paul, a Texas congressman known for libertarian views, says the killing of al-Awlaki on Yemeni soil amounts to an "assassination." Paul warned the American people not to casually accept such violence against U.S. citizens, even those with strong ties to terrorism.

al-Awlaki has been linked to the attempted Christmas underwear bomber and alleged Fort Hood shoot Nidal Hassan.

Anwar al-Awlaki was considered one of the most influential al-Qaida operatives wanted by the United States. U.S. and Yemen officials say he was killed in a U.S. air strike targeting his convoy Friday morning.

Paul made the comments to reporters after a campaign stop Friday at Saint Anselm College in New Hampshire. He said America's leaders must think hard about "assassinating American citizens without charges."