Iranian state television reported a first and then a second explosion during the ceremony in the southeastern city of Kerman, saying at least 20 people had been killed.

The semi-official Nournews said "several gas canisters exploded on the road leading to the cemetery". A local official was quoted by Iranian state media as saying "it is not yet clear whether the explosions were caused by gas cylinders or a terrorist attack".

State TV showed Red Crescent rescuers attending to wounded people at the ceremony, where hundreds of Iranians had gathered to mark the anniversary of Soleimani's death. Some Iranian news agencies said at least 50 people were wounded.

"Our rapid response teams are evacuating the injured... But there are waves of crowds blocking roads," Reza Fallah, head of the Kerman province Red Crescent told state TV.

(Writing by Parisa Hafezi;Editing by Alison Williams and Philippa Fletcher)