President Obama on Thursday offered an emotional apology for the accidental killing of two hostages held by Al Qaeda, one of them American, in a United States government counterterrorism operation in January, saying he takes “full responsibility” for their deaths, reports The New York Times.

“As president and as commander in chief, I take full responsibility for all our counterterrorism operations,” including the one that inadvertently took the lives of the two captives, a grim-faced Mr. Obama said in a statement to reporters in the White House briefing room.

“I profoundly regret what happened,” he added. “On behalf of the U.S. government, I offer our deepest apologies to the families.”

Mr. Obama’s remarks came shortly after the White House released an extraordinary statement revealing that intelligence officials had confirmed that Warren Weinstein, an American held by Al Qaeda since 2011, and Giovanni Lo Porto, an Italian held since 2012, died during the operation. The White House did not explain why it has taken three months to disclose the episode, although it typically takes some weeks after a strike to confirm the identities of casualties.

Two other Americans who belonged to Al Qaeda, Ahmed Farouq and Adam Gadahn, were also killed in American operations in the same region, the statement said. Neither had been specifically targeted and their presence at the sites of the operations was not known at the time.

Mr. Obama said he had ordered the incident declassified because the families of Mr. Weinstein and Mr. Lo Porto “deserve to know the truth.”

“The United States is a democracy, committed to openness in good times and in bad,” he said. “It is a cruel and bitter truth that in the fog of war generally, and our fight against terrorists specifically, that mistakes, sometimes deadly mistakes, can occur.”

Mr. Obama said the operation that killed the two hostages was conducted “fully consistent with the guidelines” for such missions in the region. He said that it was conducted after hundreds of hours of surveillance had convinced American officials that they were targeting an Al Qaeda compound where no civilians were present, and that “capturing these terrorists was not possible.”

What United States officials did not know, he said, was that Al Qaeda was “hiding” the captives at the site.

He said a full review was underway to identify any changes that should be made to avoid similar errors in the future.

”We will do our utmost to insure it is not repeated,” Mr. Obama said.

Even though Mr. Obama announced that the two drone strikes had been declassified, there were limits to the White House’s transparency about the two operations. Mr. Obama did not say that the Central Intelligence Agency had carried out the strikes, nor did he say that they occurred in Pakistan.

Under the terms of a secret arrangement brokered in 2004, the C.I.A. was allowed to conduct lethal strikes inside the tribal areas of Pakistan, but neither the American nor the Pakistani government could acknowledge their existence. One senior American official said that the deaths occurred during two separate strikes in Pakistan in January. One strike killed the two hostages and Mr. Farouq. A second C.I.A. drone strike killed Mr. Gadahn. It is unclear who else was killed in the two operations.