One person was killed and three were wounded in a bomb explosion in southeastern Iran, the state news agency IRNA reported, blaming a "terrorist group" linked to Tehran's enemies.

The attack reportedly occurred in the city of Saravan, the site of recent violence, in the restive Sistan-Baluchistan Province.

A group "linked to global arrogance," a phrase that in Iranian media usually describes the United States and its allies, had carried out "the explosion at one of Saravan's squares, leading to one being killed and the injury of three citizens crossing the street," IRNA said.

Sistan-Baluchistan has a border with Pakistan and its population is mainly Sunni ethnic Baluch.

The province has long been a flash point for cross-border attacks by separatists and Sunni militants.

The incident came almost one month after deadly confrontations with fuel smugglers in Sistan-Baluchistan.

Iranian authorities said two people, including a policeman in Saravan, were killed in those clashes.

But the UN Human Rights Office said at least 12 people were reportedly killed, two of them minors, and accused Iranian security forces of using excessive force.

Based on reporting by AFP and IRNA