capsized in the Channel off France overnight Thursday to Friday while attempting to reach Britain, with one person dead and another in criticaln condition, French maritime authorities said.
Among the 66 people recovered, "one unconscious victim, in critical condition, was taken by helicopter to the hospital in Calais" while a second "could not be revived," the authorities said.
French sea rescue coordinators at Griz Nez near Calais were warned during the night that a migrant boat was in difficulty less than eight kilometres (five miles) from the coast.
A rescue vessel arrived in the area at around 30 minutes past midnight (2330 GMT), maritime authorities said.
After the crew found one of the migrant boat's buoyancy tubes "deflated" and people "in the water", they brought everyone they could find back to Calais.
Boats and aircraft are still looking for remaining survivors, with French Interior Minister Gerald Darmanin expected in Calais on Friday morning.
Tens of thousands of people a year have been making the dangerous crossing over the English Channel from France in small boats, making the issue a political priority for the British government and a bone of contention between London and Paris.
The human toll has been high, with one of the worst-ever sinkings two years ago claiming 27 lives. In late November a migrant boat carrying 60 people sank and a man and woman
And in August this year, six Afghans drowned after their small boat capsized. French authorities say that boats are increasingly overloaded, with the average number of about 53 passengers nearly double the average of two years ago.
More than 28,000 people have crossed the Channel since the start of this year, according to British government statistics running to the end of November, compared with almost 46,000 over the whole of last year.