An explosion has ripped through a protest march in the Afghan capital, Kabul, with at least 20 people killed and scores wounded, officials say.
The blast hit Deh Mazang square as thousands of people from the Hazara minority marched to demand changes to the route of a planned power line.
They are angry that the route bypasses areas with large Hazara populations.
The cause of the blast is unclear, although TV channel Tolo cited reports that a suicide bomber was behind it.
No-one has yet said they carried out the attack.
'Death to discrimination'
A spokesperson for the health ministry told the BBC that at least 20 people had been killed and a further 160 protesters injured.
A freelance journalist working for BBC Afghan said blood and body parts were everywhere, with debris strewn around.
What is behind the power line protest?
A large part of Kabul's city centre had been sealed off for the protest march.
The demonstrators had waved banners and chanted "death to discrimination", angry that the 500kV power transmission line from Turkmenistan to Kabul would not pass through Bamyan and Wardak provinces, which have large Hazara populations.
The Hazaras - mostly Shia Muslims - make up the third largest group in Afghanistan. They live mainly in the centre of the country.
They complain of persistent discrimination, especially during Taliban rule in the late 1990s, when many of them fled to Pakistan, Iran and Tajikistan.
Who are the Hazaras?
- Of Mongolian and Central Asian descent
- Mainly practise Shia Islam, in predominantly Sunni Afghanistan and Pakistan
- Thought to be the third largest ethnic group in Afghanistan
- Estimates suggest they make up 15-20% of Afghanistan's population, which is thought to be about 30 million
- At least 600,000 Hazaras live in Pakistan, most of them in Quetta
- Legend has it they are descendants of Genghis Khan and his soldiers, who invaded Afghanistan in the 13th Century