Twelve Taliban fighters were killed in artillery fire along Afghanistan's border with Pakistan, officials said.
Coalition and Afghan troops in Paktika province were attacked by insurgents who used Pakistan's territory to fire rockets and mortar rounds Saturday, a statement from the U.S.-led coalition said.
Pakistani authorities gave permission for the troops to return fire, it said.
In Helmand province, coalition and Afghan troops clashed with militants near the Taliban-held town of Musa Qala late Saturday, leaving at least a dozen people dead.
The North Atlantic Treaty Organization said 12 militants were killed, but witnesses said at least 18 civilians, including women and children, died.
On Sunday, a NATO soldier was shot to death while on patrol in eastern Afghanistan, the organization said in a statement. It did not give his nationality.