Cyclone Idai has triggered a "massive disaster" in southern Africa affecting hundreds of thousands if not millions of people, the UN has said.
The region has been hit by widespread flooding and devastation affecting Mozambique, Zimbabwe and Malawi.
Mozambique's President Filipe Nyusi called it "a humanitarian disaster of great proportion".
He said more than 1,000 people may have been killed after the cyclone hit the country last week.
Cyclone Idai made landfall near the port city of Beira in Sofala province on Thursday with winds of up to 177 km/h (106 mph).
Mozambique's government said 84 people had died and 100,000 needed to be urgently rescued near Beira.
An aerial survey of the province showed that a 50km (30 mile) stretch of land was under water after the Buzi river burst its banks, charity Save The Children said.
In Zimbabwe, the government says 98 people have been killed and more than 200 are missing.
President Emmerson Mnangagwa said that the government was conducting rescue missions and delivering food aid.
Floods of up to six metres deep had caused "incredible devastation" over a huge area in Mozambique, World Food Programme regional chief Lola Castro said.
At least 1.7 million people were in the direct path of the cyclone in Mozambique and 920,000 have been affected in Malawi, the UN said.
In Zimbabwe, at least 20,000 houses have been partially damaged in the south-eastern town of Chipinge, 600 others were completely destroyed.
Local officials say they are distributing rice and maize from the national food reserve to those displaced.
What are the relief teams doing?
In Mozambique, several aid agencies are assisting government efforts in the search and rescue operations and in the distribution of food aid, ReliefWeb reports.
Telecoms Sans Frontiers has sent a team to Beira to help set up communication networks - which has been severely hindered - for humanitarian operations.
Many aid trucks are stuck on the impassable roads and unable to reach their destinations. The conditions have also limited air operations.
Mozambique's National Institute for Disaster Management is also housing 3,800 families in Sofala province.
The Red Cross has warned there could be an outbreak of waterborne diseases, including cholera, due to the expected contamination of the water supply and disruption of usual water treatment.
A cargo plane carrying emergency supplies is also scheduled to arrive in Mozambique on Tuesday.