The U.N. refugee agency says at least 20 migrants rescued at sea by the Italian navy had suffered burn injuries, some of them grave, in a cooking gas explosion before departing Libya on a smuggler's boat.

The U.N. High Commissioner for Refugees said in a statement Friday that none of the victims had been properly treated before boarding an inflatable dinghy for Italy, and at least one of the burn victims had died en route. The 20 burn victims included a 6-month-old child.

They were among 70 migrants, mostly refugees, who arrived Friday on the island of Lampedusa.

Migrants and refugees seeking a new life in Europe have been fleeing Libya in unprecedented numbers in recent days, with Italian vessels rescuing some 10,000 in the last week.