President Obama announced this morning that a U.S. anti-terror operation in January accidentally killed two al Qaeda hostages, including one American.

The White House said intelligence officials have confirmed the deaths of Warren Weinstein, who was taken hostage by al Qaeda in 2011, and Giovanni Lo Porto, an Italian aid worker held since 2012.

Weinstein went missing in Pakistan while working as a security contractor.

The operation also killed an American al Qaeda leader named Ahmed Farouq, the White House said.

"As president and as commander-in-chief, I take full responsibility for all our counter-terrorism operations, including the one that inadvertently took the lives of Warren and Giovanni. I profoundly regret what happened. On behalf of the United States government, I offer our deepest apologies to their families," said Obama. 

The White House also announced that an American al Qaeda member, Adam Gadahn, was killed in a separate counterterrorism operation. 

The president said he has ordered a "full review" of the incident. He said when the hostages' deaths were confirmed, he immediately ordered that the operation be declassified so the families would know the truth.

Citing a senior defense official, Bret Baier reported on "America's Newsroom" that the accidental deaths occurred in a CIA drone strike.

Watch Obama's remarks above.

In advance of the president's remarks, the White House released the following statement:

It is with tremendous sorrow that we recently concluded that a U.S. Government counterterrorism operation in January killed two innocent hostages held by al-Qa’ida.  Our hearts go out to the families of Dr. Warren Weinstein, an American held by al-Qa’ida since 2011, and Giovanni Lo Porto, an Italian national who had been an al-Qa’ida hostage since 2012.  Analysis of all available information has led the Intelligence Community to judge with high confidence that the operation accidentally killed both hostages.  The operation targeted an al-Qa’ida-associated compound, where we had no reason to believe either hostage was present, located in the border region of Afghanistan and Pakistan.  No words can fully express our regret over this terrible tragedy.

We also believe two other Americans were recently killed in U.S. Government counterterrorism operations in the same region.  We have concluded that Ahmed Farouq, an American who was an al-Qa’ida leader, was killed in the same operation that resulted in the deaths of Dr. Weinstein and Mr. Lo Porto.  We have also concluded that Adam Gadahn, an American who became a prominent member of al-Qa’ida, was killed in January, likely in a separate U.S. Government counterterrorism operation.  While both Farouq and Gadahn were al-Qa’ida members, neither was specifically targeted, and we did not have information indicating their presence at the sites of these operations. 

The President directed that the information being shared today, which was properly classified until now, be declassified and shared with the American people.  He takes full responsibility for these operations and believes it is important to provide the American people with as much information as possible about our counterterrorism operations, particularly when they take the lives of fellow citizens.  The uniquely tragic nature of the operation that resulted in the deaths of two innocent hostages is something we will do our utmost to ensure is not repeated.  To this end, although the operation was lawful and conducted consistent with our counterterrorism policies, we are conducting a thorough independent review to understand fully what happened and how we can prevent this type of tragic incident in the future. 

Many within our government spent years attempting to locate and free Dr. Weinstein and Mr. Lo Porto.  The pain of their deaths will remain with us as we rededicate ourselves to adhering to the most exacting standards in doing all we can to protect the American people.

Stay tuned to Fox News Channel throughout the day for the latest developments and analysis on the hostages' deaths.