Macron promises to 'rebuild' Mayotte

French President Emmanuel Macron promised to "rebuild" Mayotte during his visit to the cyclone-devastated Indian Ocean archipelago on Thursday.

Five days after Cyclone Chido left a trail of destruction in its wake, Macron said France would rebuild schools, homes and hospitals there and also crack down on illegal immigration.

He also declared a national day of mourning for the victims of the disaster for Monday.

Emergency teams are still working at full pace, searching for survivors and supplying desperately-needed aid. Macron's visit came after Paris declared "exceptional natural disaster" measures for Mayotte late on Wednesday.

France on Thursday said it had activated the European Union's Civil Protection Mechanism, a pooled response by EU members and others to disasters.