According to the White House, since this happened inside Afghanistan it should not be labelled terrorism.

Via Daily Mail:

The Taliban have claimed responsibility for an insider attack by an Afghan soldier that killed three American contractors at a Kabul airport on Thursday.

A spokesman for the insurgent group said that the attacker’s name was Ehsanullah and that he was from Laghman Province in the east of the country.

The Taliban said the soldier ‘opened fire on invaders,’ according to the Washington Post.

The Taliban said the soldier, whom they called an ‘infiltrator,’ was ‘martyred by return fire,’ the Post reports.

A fourth American was injured in the attack and the US-led coalition confirmed that an Afghan, believed to be the attacker, was killed.

The attack occurred at an Afghan military base at the North Kabul International Airport complex.

‘Insider attacks’ by Afghan security forces have been on the rise in recent years and have led to the deaths of 142 people.