Medics in Arbil treating Mohammad Mahmoudi, 27, said he was in a critical condition.

Before setting himself on fire, Mahmoudi was filmed on a video posted on social media saying he had fled Iran because he was a critic of authorities in Tehran.

"Are we supposed to live the way I live because of my political activity? Is that life?" he said. "We have been living like homeless dogs for four years".

Friends of Mahmoudi told AFP he is a former Peshmerga and dissident originally from the Boukan region, 480 kilometres (300 miles) west of Tehran, but had sought sanctuary in neighbouring Iraq's autonomous Kurdish region.

A day labourer, he submitted an application for refugee status to the United Nations four years ago, but his request was still reportedly under review, friends said.

"If I return to Iran, I will be executed," Mahmoudi said.

Thousands of Iranian Kurds, struggling amid tough economic sanctions, cross into Iraq looking for work.

The filming of the scene and the video's circulation on social media provoked an online outcry among Kurds. The video was later taken down.

There was no immediate response from the UN in Arbil on Mahmoudi's asylum status.