Suicide bombers have killed at least six people at the funeral in Kabul of a man who died during a protest on Friday, Afghan officials say.
Dozens were wounded in the blasts, which hit the funeral of one of five people killed when police fired on a protest against deteriorating security.
The chief executive of Afghanistan, Abdullah Abdullah, survived the attack.
The latest violence comes as much of Kabul is in lockdown and amid popular anger at the government.
Officials had warned people to stay away from demonstrations, saying they might be attacked by militants. Checkpoints have been set up in central Kabul, and armoured vehicles are patrolling the streets.
In a televised address, Mr Abdullah said three suicide bombers were among the mourners attending the funeral of a senator’s son who was killed in Friday’s protest.
He said that an investigation must determine how the attack happened. No group has said it was behind it.
President Ashraf Ghani said on Twitter: “The country is under attack. We must be strong and united.”
At least 87 people were wounded by the blasts, the health ministry said. Some reports suggest the death toll could be higher.
Pictures on social media showed a number of dead bodies at the scene. A witness told AFP news agency that “people were blown to pieces”.
Friday’s protest followed a bomb attack on Wednesday which killed 90 people in the city’s diplomatic district.
Afghan intelligence officials have blamed the Haqqani network, a Taliban affiliate with alleged links to Pakistan.
The Taliban denied any role and there has been no comment from so-called Islamic State militants, who are usually quick to claim attacks.
More than a third of Afghanistan is now said to be outside government control.
The US has about 8,400 troops in Afghanistan, while another 5,000 from Nato allies are in the country.