Interior ministry spokesman Siddiq Siddiqi said 13 people were wounded and four killed when a bomber blew himself up at a mosque in the southern city of Kandahar, where cabinet ministers visiting from the capital Kabul had been in attendance.
The head of the religious council for the southern province of Kandahar, Hikmatullah Hikmat, was among those killed, the government said.
"It was a suicide attack. Four people have been martyred and 13 injured. The dead include Maulavi Hikmatullah, head of the Kandahar Ulema council," said Siddiqi, referring to the dead man by his religious title.
"The bombing was in a corner of the mosque. It's a big mosque," he said, adding that it was the venue for a service in memory of Ahmed Wali Karzai, the younger brother of the Afghan president shot dead at home on Tuesday.