More than 7.1 million are estimated to have been internally displaced by Russia's war in Ukraine, having fled their homes but remained in the country, the United Nations said Tuesday.
The figure issued by the UN's International Organization for Migration is up from the 6.48 million internally displaced persons (IDPs) estimated in a first study by the IOM on March 16.
"People continue to flee their homes because of war, and the humanitarian needs on the ground continue to soar," said IOM director general Antonio Vitorino.
"Humanitarian corridors are urgently needed to allow the safe evacuation of civilians and ensure the safe transportation and delivery of much-needed humanitarian aid in order to rapidly assist those internally displaced."
Russia invaded Ukraine on February 24, causing millions to flee their homes -- including more than 4.2 million Ukrainians who have left the country entirely.
The IOM conducted its second survey between March 24 and April 1, and estimated that 7,138,715 people were internally displaced within Ukraine as of Friday.
Fifty-nine percent of IDPs were estimated to be women.
It was estimated that nearly 2.4 million people had fled the Kyiv region; 2.4 million had fled the east; and 1.7 million had fled the north.
The survey found that 41 percent of the IDPs -- 2.9 million people -- were now located in the west of the country.
It found that more than 60 percent of displaced households had children; 57 percent included elderly members; and 30 percent had people with chronic illnesses.
More than a third of displaced households indicated that they had had no income in the last month.
Safety fears
Beyond the estimated 7.1 million IDPs, "more communities in need remain trapped", said the IOM.
A further 2.9 million people were estimated to be considering leaving their homes.
As for the reasons why people are staying in their homes, 16 percent said it was not safe for them to leave; six percent said they did not want to leave family members behind; three percent said they would not know where to go, and one percent said they could not leave due to health issues.
The rapid representative assessment was conducted through interviews with 2,000 anonymous respondents aged over 18 who were contacted at random over the telephone.
The survey is used by the IOM to gather insights into internal displacement and mobility, and to assess the humanitarian needs in Ukraine.
The IOM said cash, transportation, food, shelter and hygiene items were among the most pressing needs for displaced people.
IDPs also need greater access to medicines and health services, the organisation said.