A suicide bomber has attacked a mosque in Kandahar during a memorial service for the assassinated half-brother of Afghan President Hamid Karzai, officials say.
Four people were killed, including the top cleric of the provincial council.
Ahmad Wali Karzai, a controversial but key figure in Nato's battle against the Taliban, was killed by his bodyguard.
President Karzai flew into Kandahar for his brother's funeral on Wednesday, but did not attend Thursday's service.
No group has so far admitted carrying out the mosque attack.
Chaos and panic
The explosion took place just after noon in the southern Afghan city.
"It was a suicide bombing. It was inside the mosque," a member of Kandahar's provincial council said.
"The service was about the end when it happened," the official added.
An eyewitness told the BBC that "someone was trying to get inside the mosque" before the blast.
The suspected attacker was stopped at the mosque's entrance, and he then blew himself up.
Some reports suggest the bomber hid the explosives in his turban.
Four people were killed and 13 injured after the blast, officials say.
The Afghan interior ministry said that among those killed was Hikmatullah Hikmat, the head of Kandahar's Ulema Council. The council is an influential body of clerics in charge of regulating religious issues in the province.
Four of President Karzai's brothers and the governor of Kandahar were in the mosque at the time.
The BBC's Bilal Sarvary in Kandahar reports that senior defence ministry officials were inside the mosque.
Elite police units have arrived in the area, our correspondent says, adding that there are currently scenes of chaos and panic in the area.
Appeal to Taliban
Ahmad Wali Karzai was shot twice by his family friend and long-time head of security, Sardar Mohammed, on Tuesday. The bodyguard was himself killed almost immediately.
The Taliban said that the attack was one of their top achievements in 10 years of war.
Ahmad Wali Karzai was seen by many as a key anti-Taliban figure, someone who stood up to them, using his private army and vast network to fight the insurgents, our correspondent says.
But he adds that his critics accused him of undermining the central government in Kabul.
On Wednesday, President Karzai wept at the graveside, and kissed his dead half-brother's face as senior politicians looked on.
The president then appealed to the militants to stop the bloodshed.
"My message for the Taliban is, my countryman, my brother, stop killing your own people," said Mr Karzai. "It's easy to kill and everyone can do it, but the real man is the one who can save people's lives."
Tuesday's killing was the latest and most high-profile in a series of assassinations of senior politicians and security commanders across the country.
