Pakistani security forces had cleared Swat valley in a major operation in 2009.
Outlawed militant group Tehreek-e-Taliban claimed the attack, according to the media reports.
"The soldiers were playing volleyball in the evening outside the military base. when a suicide bomber managed to blow himself up", an official told Reuters. The Taliban also warned more attacks in near future.
Security forces have cordoned off the area and are searching for possible accomplices of the bomber.
Government sources had said rescue teams reached the area and shifted the injured to a hospital in Saidu Sharif. The operation involved evacuating 2 million people from the valley.
Turkeyyesterday condemned Saturday's terrorist attack in Pakistan which killed several soldiers.
"No cowardly attack can deter us in pursuing our struggle against the menace of terrorism to its logical conclusion".
Since then peace has returned to the area popular with domestic and foreign tourists, and militant attacks have become extremely rare in the valley known as Pakistan's Switzerland.
Parts of the vallery had become strongholds of the Pakistani Taliban between 2007 and 2009.