Greece's prime minister has expressed shock at the deaths of a woman and child in a fire that raged through an island refugee camp used for migrants facing deportation back to Turkey.

Alexis Tsipras said Friday he was "shocked, as is the entire Greek nation, by the tragic event" on Lesbos overnight. Police said a cooking gas canister sparked the fire, and that the victims were a young boy and an older woman. Another woman and a second child were severely injured and flown to Athens, where they were hospitalized in serious condition, while several others were less seriously hurt.

Migrants at the camp clashed with police as they were evacuated from the camp during the blaze, which was extinguished by firefighters.

Protests have repeatedly occurred at overcrowded deportation camps.