A suicide bomber killed 13 people and wounded 13 on Tuesday when he set off explosives outside the police headquarters in the southern Afghan city of Kandahar, a government spokesman said. A Taliban spokesman, Qari Mohammad Yousuf, claimed responsibility on behalf of the group, telling Reuters by telephone from an undisclosed location the bomber came from Kandahar. "Thirteen people were killed and 13 wounded. Seven of the dead are police," an Interior Ministry official said. Some of the wounded were in a critical condition, officials said. The bomber detonated his explosives during a search as he tried to enter the police compound on his motorcycle, said Interior Ministry spokesman Yousuf Stanizai. Also on Tuesday, a bomb hidden on a bicycle exploded in the town of Spin Boldak, which is near the Pakistani border in Kandahar province, wounding three civilians, police said. Dozens of people have been killed in a wave of attacks, including 14 suicide blasts, across southern and eastern Afghanistan in recent months.