UNITED NATIONS, United States -- The UN's emergency relief coordinator called on Friday for "safe, unimpeded access" for aid workers to carry out humanitarian operations in Ukraine, after the Russian invasion.
Martin Griffiths told reporters at the United Nations headquarters in New York that it wasn't yet clear how many people were in need of help.
But he said he does expect a further 1.8 million Ukrainians to be displaced on top of the 100,000 or so that the UN estimates have already been driven from their homes.
"We need the safe, unimpeded access and protection of our humanitarian workers and the deliveries that they will be doing... as soon as the security allows it to all areas of Ukraine affected by conflict," said the under-secretary-general for humanitarian affairs.
The UN refugee agency has warned that some 100,000 people have already been displaced.
The United States ambassador to the UN warned this week that the war could ultimately displace as many as five million people.
Griffiths said that an appeal for funds would be launched in Geneva within the coming days.
"We're now beginning to realize that the scale of need in these very, very extraordinary circumstances is going to be of the highest," he added.
Griffiths said that at this stage all UN teams remain in Ukraine, although non-essential personnel and their families were being temporarily relocated within the country.