GENEVA, March 19 (Xinhua) -- A International Federation of the Red Cross and Red Crescent Societies (IFRC) official Tuesday described damage caused for 1.7 million people in the path of Tropical Cyclone Idai as the worst humanitarian crisis in Mozambique's history.

IFRC spokesperson Matthew Cochrane said at a UN press briefing here that rescuers are scrambling to pull people trapped on rooftops and in trees to safety in the port city of Beira with a population of more than half a million.

He cited Jamie LeSueur, who is leading IFRC response efforts in Beira saying, "This is the worst humanitarian crisis in Mozambique's history. It is a humanitarian catastrophe for the people of Central Mozambique."

UN agencies such as the World Food Program (WFP) and the UN Children's Fund, UNICEF, along with the IFRC appealed for immediate international funding to support those with no access to food or clean water in Mozambique, Zimbabwe, and Malawi.

Herve Verhoosel, senior spokesperson for the UN World Food Program (WFP) quoted Mozambique government estimates that 600,000 people have been affected by floods in the aftermath of Cyclone IDAI in the country's provinces of Sofala, Manica, Zambézia, Inhambane, and Tete.

"Preliminary WFP satellite-derived projections indicate at-least 1.7 million people were in the direct path of the cyclone in Mozambique, and 920,000 people were affected in Malawi," said Verhoosel.

"Thousands more are potentially impacted by events in Zimbabwe where assessments are ongoing."

Lola Castro, WFP Regional Director for Southern Africa, said in a phone interview with reporters in Geneva, "People visible from the air may be the lucky ones, and the top priority now is to rescue as many as possible and ferry them to safety."