WASHINGTON: US President Barack Obama acknowledged Friday that “civilians were killed that shouldn't have been” in past US drone strikes, but said the administration is now “very cautious” about striking where women or children are present.

Obama was asked at a news conference about an increase in the number of people targeted in drone strikes against extremists in Libya, Syria, Somalia and elsewhere.

“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,” Obama said. “There's no doubt that civilians were killed that shouldn't have been.”

He added that over the last several years, the administration has worked to prevent civilian deaths.

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

Recent drone and other airstrikes against extremist targets have killed large numbers of people.

A strike on a training camp of the militant Islamic State group in western Libya in February killed more than 40 people; a drone strike in Somalia against al-Shabab on March 5 killed 150 people.

A drone strike in Yemen in February killed dozens.

The US came under heavy criticism for a drone strike several years ago against extremists in Yemen, which critics said actually hit a wedding party and killed women and children.

In October, an AC-130 gunship mistakenly hit a hospital in Afghanistan that was run by the charity organisation Doctors Without Borders.

The group has demanded that the strike be investigated as a war crime. The Pentagon disciplined several officers and enlisted personnel for their part in the attack.

Obama said Friday the US uses “vigorous criteria” for getting intelligence on targeting, and that intelligence is “checked, double-checked, triple-checked before kinetic actions are taken.”

He said the US is targeting camps that are clearly “involved in and directing plots that could do the United States harm or are supporting ISIL activities or al Qaeda activities.”

Then, he said, “a strike will be taken. “

Comments like Trump's show ignorance about world

US President Barack Obama said Friday that suggestions from people like Donald Trump that nuclear weapons would help South Korea and Japan show a lack of understanding of the world.

The Republican presidential front-runner told The New York Times last week he would be open to Japan and South Korea having their own atomic arsenals as a deterrent to North Korea.

When asked about the issue Friday night, Obama said, “The person who made the statements doesn't know much about foreign policy or nuclear policy or the Korean Peninsula or the world generally.”

He described the US alliance with Japan and South Korea as “one of the cornerstones of our presence in the Asia-Pacific region.”

US policy there, he said, “has prevented the possibilities of a nuclear escalation in conflict between countries that in the past and throughout history have been engaged in hugely destructive conflicts and controversies. So you don't mess with that.”

Obama added, “And we don't want somebody in the Oval Office who doesn't recognise how important that is.”

Without naming specific candidates, Obama noted that the hectic campaign to replace him had come up during discussions with leaders at this week's nuclear summit in Washington.

“What we do is really important to the rest of the world,” he said. “And even in those countries that are used to a carnival atmosphere in their own politics want sobriety and clarity when it comes to US elections. “