Eight Pakistani soldiers have been injured after being hit by a shell fired from across the Afghan border, officials and witnesses said.
Officials said 10 more shells landed in a nearby forest area, damaging trees but causing no loss of lives.
The targeted military post is located several hundred metres inside the Pakistani border.
Last month, 11 Pakistani troops were killed in an air strike by Afghanistan-based US forces.
Officials in Pakistan say the shells were fired by coalition troops operating in the Barmal area on the Afghan side of the border.
An official in Pakistan's South Waziristan province told the BBC Urdu service that the injured had been airlifted to a hospital in Wana, the provincial headquarters.
An army source in Islamabad confirmed the strike and injuries, but offered no further details.
Alleged US missile strikes have sparked anger in Pakistan
A US air strike at an army border post in Mohmand tribal district on 11 June killed 11 Pakistani soldiers and some suspected militants.
Lately, US media quoting US officials has been predicting more strikes in the Pakistani territory in coming days.
There is increasing anger in Pakistan at US strikes on its territory which have killed more than 50 people this year.
Taleban fighters have a strong presence in Pakistan's border area and tribal districts - local administrators have little power there, although security forces keep a presence on the border.
Afghan and US-led forces accuse Islamabad of not doing enough to deny Taleban militants a hiding place in Pakistan's tribal areas and stop them from infiltrating the border into Afghanistan.
Pakistan denies the accusations, saying it has lost about 1,000 soldiers fighting militants in the tribal border areas.