WASHINGTON — Two years ago, President Barack Obama stood before a military audience and spoke of the “heartbreaking tragedy” of accidental civilian deaths caused by U.S. military strikes in the fight against terrorism in places like Pakistan and Afghanistan.

Now, with news of the death of two Western hostages in a CIA drone strike — American Warren Weinstein and Italian Giovanni Lo Porto — the president has received a brutal reminder that every U.S. commander-in-chief may have to face the loss of civilians as collateral damage in wartime.

“It is a cruel and bitter truth that in the fog of war generally and our fight against terrorists specifically, mistakes, sometimes deadly mistakes, can occur,” Obama said.

Today, the Pakistan Ministry of Foreign Affairs issued a statement of condolences to the hostages’ families.

“Having lost thousands of innocent civilians in the war against terrorism, Pakistan can fully understand this tragic loss and stands with the families of Weinstein and Lo Porto in this difficult time,” the ministry said. “The death of Mr. Weinstein and Mr. Lo Porto in a drone strike demonstrates the risk and unintended consequences of the use of this technology that Pakistan has been highlighting for a long time.”

Meanwhile, in Italy, Foreign Minister Paolo Gentiloni is seeking to explain to Parliament why it took three months to learn about the death of Lo Porto in the U.S. drone strike. Gentiloni told lawmakers today that in an inaccessible war zone, where hostage-taking is frequent, it took that long for U.S. intelligence to verify Lo Porto had been killed.

Michael O’Hanlon, a national security and defense specialist at the Brookings Institution, said it’s inevitable that “if you try to use drones to kill terrorists, you’re going to sometimes hurt innocent people.”

He said the U.S. goes to great lengths to protect civilians, “but you’re never going to be 100 percent certain.”

O’Hanlon said the U.S. had already begun limiting its use of armed drones in Pakistan because of Pakistani concerns and exaggerated claims of civilian casualties in that country.