Iran has released the last two of eight Slovak paragliders who were arrested in May for allegedly spying, the official news agency IRNA reported.

"Two citizens who were arrested for violating the laws of the Islamic republic of Iran were released and handed over to their embassy" on Wednesday, said IRNA on Thursday.

The six other Slovaks were released in September.

In July, Iran's judiciary said it was probing nine people - the eight Slovaks and one Iranian - arrested for "illegal activities, including photographing restricted areas" in the central Isfahan province, which is home to nuclear facilities including the Natanz uranium enrichment site.

Isfahan is located some 330 kilometres south of the capital Tehran.

The international community has imposed a battery of sanctions against Iran, accusing it of using its civilian nuclear energy programme as a cover for developing atomic weapons - charges Tehran flatly denies.

Friends of the paragliders have told AFP news agency they were not spies, but were travelling to film documentaries from a bird's-eye view.

They said the men were in Iran to collect material for a second film, after making a documentary last year on paragliding over the Himalayas.

Senior Iranian prosecutor Gholam Hossein Mohseni Ejeie asserted the men had smuggled in unspecified "equipment".

The paragliders ran into trouble for using two-band walkie talkies reportedly banned in Iran, as well as cameras designed for extreme sports.