WASHINGTON — Three US soldiers were killed and another wounded in an attack in eastern Afghanistan Saturday.

The incident is being described as an “insider attack.”  Reports indicate the rangers were shot and killed by an Afghan soldier.  

A statement from the Department of Defense said the “incident is under investigation. Additional information will be released as appropriate.”

President Trump has been briefed on the situation.

Vice-President Mike Pence spoke about the incident to the crowd at Saturday’s Road to Majority Conference in Washington.

“The details of this attack will be forthcoming. But suffice it to say, when heroes fall, Americans grieve. And our thoughts and prayers are with the families of these American heroes,” said Pence.

The Achin district, where the attack is believed to have occurred, is described as an ISIS and Taliban stronghold. 

US special forces have been fighting alongside Afghan soldiers to take down both groups. 

More than 8,000 US troops remain in Afghanistan.