An explosion at a prominent Shia mosque in the southeast Iranian city of Zahedan killed 30 people and wounded 60.

The news agency ILNA said the blast was a suicide bombing but no person or group had claimed responsibility.

Shortly after the explosion, security forces discovered and defused a second bomb near the mosque.

The attack was carried out on a public holiday honouring the first Shia Imam, Ali Ebne-Abitaleb, after whom the mosque is named.

Zahedan is a mostly Sunni city.

Zahedan is the capital of Sistan-Baluchestan province which shares a border with Pakistan. The province faces serious security problems and there are frequent clashes between police and drug dealers and bandits.

A bomb attack in Zahedan in February 2007 which killed 18 Revolutionary Guards was claimed by Jundallah, an insurgent group that says it is fighting for the rights of Iran's Sunni Muslim minority.