Three U.S. Army Rangers were killed and another wounded during an attack in eastern Afghanistan, according to three U.S. officials, speaking on condition of anonymity.

Fox News reported that the Taliban had taken credit for the attack.

A local Afghan official said earlier two U.S. soldiers were killed and two others wounded during the shooting in Achin district, where U.S. special forces have been fighting alongside Afghan troops against Islamic State and Taliban militants.

Attahullah Khogyani, spokesman for the provincial governor in Nangarhar province, said that two other U.S. soldiers are wounded in the attack, which took place in the Achin district. He said the Afghan soldier was killed after the attack.

Such insider attacks have happened before in Afghanistan. In March, another Afghan soldier was killed after he opened fire on foreign forces at a base in Helmand province, wounding three U.S. soldiers.

"I was informed U.S. Service members were attacked and killed in Afghanistan. The president and I have been briefed. The details will be forthcoming, "Vice President Mike Pence told employees at Direct Supply Inc. in Milwaukee, which builds and provides equipment to long-term car and senior living communities.

"When heroes fall, Americans grieve," Pence said. "Our thoughts and prayers are with the families of these American heroes."

Information from Reuters and The Associated Press was used in this report.