The death toll from Cyclone Chido's rampage through the French overseas territory of Mayotte remained unclear on Wednesday, with shantytowns that were home to undocumented migrants flattened and many areas still inaccessible.

French President Emmanuel Macron said he would visit territory on Thursday, cutting short his participation at the European Council meeting.

France from Tuesday evening will impose a nighttime curfew on the Indian Ocean island of Mayotte, after the French overseas territory was devastated by a cyclone feared to have killed hundreds, the interior ministry said.