A bomb exploded at an Afghan refugee camp in northwestern Pakistan killing four people and wounding five more on Monday, police said.
The motive for the attack at the Jalozai Afghan Refugee Camp in Nowshera was not immediately clear.
The camp lies about 50 kilometres east of Peshawar, the capital of North West Frontier Province.
Mohammed Tahir, an area police chief, said two Afghan refugees died on the spot and two more died at a hospital. Five others injured were in a stable condition, he said.
"We have no idea what exactly caused this explosion, but apparently it was some explosive device," he said, adding that officers had arrived at scene and bomb disposal experts were investigating.
The dead and injured were Afghan refugees, he said. Tens of thousands of Afghan refugees have been living at the Jalozai Refugee Camp and elsewhere in Pakistan since fleeing their homeland during a quarter century of war starting with the Soviet occupation in the 1980s.