A suicide bomber tore through a crowd of Afghan demonstrators on Monday, killing 21 people in the northern city of Kunduz, a hospital doctor said, amid fears that the toll could rise further.
Doctor Shir Jan, who works at the Kunduz central hospital, said 21 bodies -- one of them a woman -- had been brought in after the attack. Both civilians and policemen were among the dead, he added.
A policeman deployed to man the demonstration, Gul Agha, told AFP that 18 people had died, including six civilians and 12 law enforcement police.
There were local reports that the demonstration was in support of a local warlord accused of killing civilians.
Monday's bombing comes just two days after a suicide bomber, whom Afghan police identified as a teenager, blew himself up outside Nato headquarters in Kabul, killing six youngsters aged 12 to 17.
The Taliban insurgency that has raged for 10 years against Western troops and the Kabul government is traditionally centred in the south and the east, but Kunduz in the north has seen an increase in violence in recent years.
Last month, a bomb attached to a motorcycle killed 10 people in a market elsewhere in the province, in Archi district near the border with Tajikistan.