At least 40 people have been killed in two separate attacks on Shia Muslim mosques in Afghanistan, officials say.
A gunman entered the Imam Zaman mosque in the capital Kabul before opening fire and detonating an explosive, killing more than 30 worshippers.
A second attack in Afghanistan's Ghor province killed at least 10 people.
No group has so far said it carried out the attacks, but so-called Islamic State (IS) has previously targeted Shia mosques across Afghanistan.
An eyewitness told the BBC that the scene at Kabul's Imam Zaman mosque, in the west of the city, "looks like a front line".
The attacker is reported to have opened fire as worshippers gathered for Friday prayers, before detonating a bomb.
Kabul police spokesman Basir Mojahid confirmed the incident at the Shia mosque in Kabul, but did not give further details.
A spokesman for the Afghan interior ministry said investigators were working at the scene to determine the "nature of the explosion," AFP news agency reports.
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Meanwhile the attack on the Shia mosque in the country's central Ghor province also killed a pro-government militia commander, according to reports.
Details of the attacks remain unclear and the number of casualties is likely to rise. Dozens of worshippers were also injured in the attacks, Afghan's health ministry said.
Friday's attacks come just days after police in Kabul said they had arrested a would-be suicide truck bomber, averting a major incident.
In August, more than 20 people were killed in a bomb attack against worshippers in Kabul.
A truck bomb in the Afghan capital in May killed more than 150 people and wounded some 400 more, most of them civilians.
