The mayor of a French coastal town being used in a rescue operation says 13 migrants are dead after their boat ripped apart Tuesday during an attempted crossing of the English Channel.

Dozens of people plunged into the treacherous waters of the busy channel.

"Unfortunately, the bottom of the boat ripped open," said Olivier Barbarin, mayor of Le Portel near the fishing port of Boulogne-sur-Mer, where a first aid post was set up to treat victims. "It's a big drama."

A maritime rescue official who spoke on condition of anonymity because he was not authorized to discuss details of the operation confirmed that at least 13 migrants were dead.

Etienne Baggio, a spokesperson for the French maritime prefecture that oversees that stretch of sea, said "more than 10" people were dead but he didn't have an exact number. The prefecture said the boat got into difficulty off Gris-Nez point.

Both Baggio and the mayor said rescuers recovered 61 people from the waters.

Sea temperatures off northern France were around 20 C.

At least 30 migrants have died or gone missing while trying to cross to the U.K. this year, according to the International Organization for Migration.

At least 2,109 migrants have tried to cross the English Channel on small boats in the past seven days, according to U.K. Home Office data updated Tuesday. The data includes people found in the channel or on arrival. Tens of thousands have made the trip since 2018.