The US has confirmed that seven American service members have been injured in an insider attack in Afghanistan. Earlier reports said four US troops were killed in an apparent attack by an Afghan soldier at an Afghan military base.

The US military command in Kabul confirmed that an unspecified number of American soldiers were injured in an incident at a base in northern Afghanistan on Saturday, but denied that there were any fatalities among US service members.

Later, the US military command in Kabul confirmed that seven US servicemen were injured in the attack and evacuated for treatment, adding that the circumstances of the attack are still being investigated.

Abdul Qahar Araam, spokesman for the Afghan Army’s 209th Corps, said earlier that the Americans were “shot and killed” by an Afghan solider, Reuters reported.