Idal in Mozambique
Clse to 100 died in Zimbabwe.
Mr Nyusi flew over some of the worst-hit areas on Monday. He described seeing bodies floating in the rivers.
The storm made landfall near the port city of Beira on Thursday with winds of up to 177 km/h (106 mph), but aid teams only reached the city on Sunday.
A UN aid worker told the BBC that every building in Beira - home to half a million people - had been damaged.
Gerald Bourke, from the UN's World Food Programme, said: "No building is untouched. There is no power. There is no telecommunications. The streets are littered with fallen electricity lines.
"The roofs on so many houses have fallen in, likewise the walls. A lot of people in the city have lost their homes."
The storm made landfall near the port city of Beira on Thursday with winds of up to 177 km/h (106 mph), but aid teams only reached the city on Sunday.
A UN aid worker told the BBC that every building in Beira - home to half a million people - had been damaged.
Gerald Bourke, from the UN's World Food Programme, said: "No building is untouched. There is no power. There is no telecommunications. The streets are littered with fallen electricity lines.
"The roofs on so many houses have fallen in, likewise the walls. A lot of people in the city have lost their homes."
