ISLAMABAD, Sept. 27 (Xinhua) -- At least 30 people were killed as two NATO helicopters struck inside Pakistan in its northwest tribal area bordering Afghanistan in the wee hours of Monday, reported local media Express.

According to the report, the Afghanistan-based NATO helicopters fired at the militants hiding in the Pakistani side who earlier launched an attack at a NATO check post in the Khost area of Afghanistan. But the report failed to say when the check post was attacked by the militants.

Most of the people killed in the incident were believed to be militants.

It was a rare incident in which NATO troops launched military actions against the militants within the territory of Pakistan. So far there is no response yet from the Pakistani government regarding the incident.