Six people have been killed after a boat carrying migrants heading to Britain sank in the English Channel early Saturday, French maritime officials said, as a search continued to find those still missing.

A spokesperson from the French coastal authority Premar said between five and 10 passengers were still missing, while 55 had been rescued.

Four French ships and a helicopter plus two British vessels were involved in rescue efforts off Sangatte in northern France, authorities said, adding that some survivors were rescued by the British vessels.

Earlier officials had reported that one man was killed and five others were in a critical condition.

(With input from AFP)