A Baluchi opposition group called Jundallah said on Friday it was behind a blast in a crowded Shi'ite mosque that killed 25 people on Thursday, Saudi-owned Al Arabiya television said.

The Dubai-based station said a man called the channel saying it was a suicide attack aimed at Iranian Basij forces meeting inside the mosque to coordinate election strategy.

It was not possible to verify the claim.

Thursday's explosion, which some officials and media suggested was a suicide bombing, took place on a religious holiday in the mainly Shi'ite Muslim country. More than 80 people were wounded.

The official IRNA news agency put the death toll at 25 and named most of the victims, all males. Other media gave lower figures.

Jalal Sayyah, of the governor's office in Sistan-Baluchestan province, said earlier three people had been arrested over the blast in the city of Zahedan, in a region where many of Iran's minority Baluchis live.

Reuters