Afghan authorities say they have found the bodies of five soldiers reported kidnapped.
The soldiers had been driving through the violence-plagued southern province of Zabul when they disappeared on Monday. Their bodies were recovered Tuesday.
The kidnapping came the day after militant attacks that took the lives of at least four other Afghan soldiers.
Reports say militants loyal to Afghanistan's former hard-line Taleban regime have claimed responsibility for the killings.
Zabul Province's mountainous Dai Chopan district previously was a stronghold for remnants of the Taleban, who have been leading an armed insurgency since the government was ousted more than two years ago.
Afghan and U.S. forces continue to pursue the Taleban fighters, although the government says it has convinced some Taleban leaders to lay down their arms and abandon the insurgency.
While attacks on government targets had eased earlier this year, insurgent violence has risen again over the past month across the east and south of the country.
The commander of U.S. forces in Afghanistan, Lieutenant General David Barno, says part of the increase is due to the warmer spring weather.
But he adds that the Taleban also are seeking to disrupt plans for Afghanistan's first national election in over a decade.
"This is the time where the remnants of the Taleban typically look to reassert their visibility and their presence here in the country," he said. "This year ? I think they're particularly desperate to do that because we're in the midst of a very successful political process here in Afghanistan."
The election originally was set for June, but security problems from the insurgency have delayed voter registration, and the vote is now scheduled for September.