Drone warfare has become a symbol of post-9/11 wars in Afghanistan, Iraq, Libya and other countries. The Obama administration has continuously expanded the drone program over two presidential terms, drawing heavy criticism for the extent of civilian deaths – also known as “collateral damage.”

Speaking at a press conference on Friday, President Obama was asked to comment on the rising death toll in US drone strikes in the Middle East and beyond.

“In the past, there was legitimate criticism that the legal architecture around the use of drone strikes wasn’t as precise as it should have been,” he said, as cited by AP.

“There’s no doubt that civilians were killed that shouldn’t have been.

“In situations of war, you know, we have to take responsibility when we’re not acting appropriately,” Obama added.

He claimed that, in general, the US military and CIA – the main drone operators – use “vigorous criteria” to gather the intelligence used in targeting, and that this intelligence is “checked, double-checked, triple-checked before kinetic actions are taken.”

The president’s straightforward acknowledgment of civilian deaths caused by drone strikes stands out among his previous statements on the issue. To date, Washington has preferred to downplay public criticism by making formal apologies or denying any wrongdoing.

Unmanned aerial vehicles (UAVs) have been actively utilized by the Pentagon and CIA for more than a decade of the so-called war on terror. At first, drones were used to gather aerial intelligence, but later turned into an effective remote-controlled weapon to eliminate high-value figures in Al-Qaeda and other terrorist organizations.

However, drone strikes have never been a precision weapon. In one recent notorious case, two Serbian embassy workers abducted in Libya were killed in a February US airstrike on a suspected Islamic State training camp. The Pentagon, which saw the attack as “very successful,” denied any wrongdoing.

In January 2015, another drone strike in Pakistan killed two US citizens linked to Al-Qaeda, but also American development expert Warren Weinstein and Giovanni Lo Porto, an Italian aid worker.

In Pakistan alone, CIA drones strikes have killed nearly 2,400 people since 2004, according to a report by the London-based Bureau of Investigative Journalism. Despite US claims it just hits “confirmed terrorist targets,” only 84 of the victims have been named Al-Qaeda members.