Eleven members of Iran's Revolutionary Guards have been killed following a car bomb attack in southeastern Iran.
The blast targeted a bus which was taking the soldiers from their housing compound in the city of Zahedan to a military base.
A further 31 people were wounded in the attack.
The city of Zahedan lies in the province of Sistan-Baluchestan, which borders both Afghanistan and Pakistan.
Jundallah, a Sunni militant group which has been blamed for a string of similar incidents in the area, claimed responsibility for the attack.
Earlier this year, four members of the Iranian security forces were killed when armed men opened fire on their vehicle. And another car bomb in Zahedan in December left one person dead.
Iranian officials have accused Britain and the US of supporting ethnic minority rebels operating in the sensitive border areas.
Bomb attacks in the provincial capital of Ahvaz in October 2005 killed six people and wounded nearly 100 and a blast in January 2006 left eight dead.
An unverifiable website message this morning, which was attributed to Jundallah, claimed the Zahedan bombing was in revenge for the recent executions of those found guilty of the Ahvaz attacks.