KABUL, Afghanistan, June 22 (UPI) -- A suicide bomber set off an explosion Wednesday near a checkpoint in Afghanistan's Ghazni province, killing at least six policemen, authorities said.
The attack occurred in the Qara Bagh district, Ghazni police chief Zaror Zahed said, CNN reported.
The attack was followed by a gunfight between militants and police, Zahed said.
"After the suicide attack on the checkpoint, the gunfire ... started between policemen and probably some other militants in the area, and we don't have any figure of casualties right now," he said.
Violence has escalated in Afghanistan lately and the latest attack comes ahead of U.S. President Barack Obama's scheduled broadcast address to announce plans for the start of U.S. troop withdrawal from Afghanistan.