— Two American soldiers and an American civilian working with them were killed in a so-called insider attack Saturday in Afghanistan, officials said.

In a second attack on international forces, an Italian soldier was killed when a grenade was thrown at him.

In the insider attack, which took place at a base in Paktika province near the border with Pakistan, a soldier with the Afghan National Army opened fire during lunchtime in the base’s dining room, killing two of the American soldiers serving with him and the civilian, according to Afghan military officers from the 203rd Thunder Corps.

The international military coalition here confirmed that the attacker had been wearing an Afghan National Army uniform, but, in keeping with military policy, did not specify the place or circumstances because an investigation was continuing.

The gunman, a company commander, was killed almost immediately, the Afghan army officers said.

Gen. Zahir Azimi, an Afghan Defense Ministry spokesman, confirmed the shooting but said he had little information about the gunman, in part because foreign troops quickly surrounded the area and the Afghans were not able to investigate.