WASHINGTON — President Donald Trump defended the continued U.S. military presence in Afghanistan as critical to national security in a Washington Post interview on Tuesday and promised to visit America troops stationed there “at the right time.”

The comments came just hours after the deaths of three U.S. service members in a roadside bomb attack in Ghazni and a few days after Army Ranger Sgt. Leandro Jasso was killed in a friendly fire incident over the weekend.

Thirteen American troops have been killed in the country since the start of the year. More than 2,400 U.S. military personnel have died in the now 17-year-old conflict.

When asked about the recent deaths, Trump expressed his condolences but also defended the ongoing mission there.

“We’re there because virtually every expert that I have and speak to say if we don’t go there, they’re going to be fighting over here,” Trump told the newspaper. “And I’ve heard it over and over again.”

He said negotiations are ongoing with Taliban groups and Afghan officials looking towards a possible end to the fighting, but did not offer any timetable for that work.

“They would like to see it after all these years, and we’ll see what happens,” he said. “A little bit too early to say what’s going to happen. But we are talking about things.

“But it’s a very sad situation when I look — we have incredible people, incredible fighters. … It’s very sad.”

During his 2016 presidential campaign, Trump indicated he would look to end U.S. military involvement in Afghanistan. But since he took office, he has gone along with Pentagon officials recommendations to increase the troop presence there, in an effort to stabilize the still inexperienced Afghan security forces.

About 16,000 U.S. troops are currently deployed in Afghanistan in training and counterterrorism roles.

Trump also did not offer any specific timeline for when he might visit the country. The president has come under increasing scrutiny in recent weeks for not making any trips to meet with troops serving in combat zones overseas, something his previous two predecessors did earlier in their terms.

White House officials have said plans for such a trip are under discussion.

Meanwhile, Defense Secretary Jim Mattis last week said he has discouraged the commander in chief from some such visits, because of security concerns surrounding both Trump and the troops who would have to manage the trip.