Iran's Press TV said on Thursday that the guards exchanged fire across the border, near the southwestern town of Kang, Nimroz province.

The English-language channel said Afghan officials said they would hand over the body of the dead officer and release the guard.

A joint committee from the two neighbours were to travel to the scene to investigate the incident, according to the report.

Iran and Afghanistan share a long border in a volatile area, where Iranian security forces have often clashed with drug smugglers.