An estimated one million people have been displaced inside Ukraine by the Russian invasion, the UN refugee agency said Tuesday, in addition to hundreds of thousands who have fled elsewhere.

“There has been a lot of attention on those who flee to neighbouring countries, but it’s important to remember that the largest number of people affected are located within Ukraine,” Karolina Lindholm Billing, UNHCR representative to Ukraine, told reporters in Stockholm.

“We still don’t have reliable figures regarding the number of people displaced inside Ukraine, but we estimate that it has to be about one million people who have fled internally or who are currently on a train, a bus or in a car trying to get to safety,” she added.

UNHCR is currently working to step up assistance within the borders of the war-torn country. 

“There is really an immeasurable humanitarian need,” she said, citing the need to house or feed displaced people.

At the same time in Geneva, the UNHCR announced that 660,000 people had already fled Ukraine to neighbouring countries and that figures were increasing “exponentially”.

“We have now over 660,000 refugees who have fled Ukraine to neighbouring countries in the past six days alone,” spokeswoman Shabia Mantoo told reporters.