Two people were killed and two others were injured after a fire broke out at a migrant camp on the Greek island of Lesbos late on Thursday, a police official told Reuters.

The official said that a 66-year-old woman and a six-year old child were killed when a tent caught fire in the camp of Moria. Two other people were seriously injured.

Police and the fire brigade were investigating the scene, a government official said, adding that initial evidence showed the fire was probably caused by accident.

Clashes broke out following the incident between dozens of migrants and police, officials said. The government official said the skirmishes were brief.

More than 6,000 migrants and refugees are stranded on the island of Lesbos, twice the capacity of state facilities.

Tensions have boiled over at overcrowded camps in the country, which is also struggling to emerge from a debt crisis, as the slow processing of asylum requests adds to frustration over living conditions.

Under a European Union deal with Turkey, migrants and refugees arriving after 20 March are to be held in centres set up on five Aegean islands, including Lesbos, and sent back if their asylum applications are not accepted.