A suicide bomber has attacked a convoy of police vehicles in south-western Afghanistan, killing 16 people, including a police commander, and wounding 28.

Mohammad Younus Rasouli, deputy governor of Farah province, said the bomber, who had been wearing women's clothes, killed four policemen and 12 civilians in the main market of Farah's Del Aram district, close to the border with Iran.

Rasouli said a police commander was among the four dead.

Officials in the provincial hospital gave the number of wounded as 28 with most being civilians.

Rasouli said 22 people were wounded in the attack.

Taliban militants claimed responsibility for the attack in a statement posted on their website.

The statement said the dead police commander was the target, adding that one of their male fighters by the name of Khalid carried out the attack.