Russian President Vladimir Putin has warned that he would consider any declaration of a no-fly zone over Ukraine by a third party as participation in the war there.

On Saturday, Mr Putin said Russia would view “any move in this direction will be viewed by us a participation in the armed conflict of whichever side whose territory will pose a threat to our service members”

Ukraine’s president Volodymyr Zelensky had implored that NATO and Western powers enforce a no-fly zone over Ukraine, saying “all the people who die from this day forward will also die because of you” if the no-fly zone was not imposed.

On Friday, the North Atlantic Treaty Organisation(NATO) said it was not seeking conflict with Russia.

The defence bloc said that imposing a no-fly zone over Russia, which would prevent all unauthorized aircraft from flying over Ukraine and may mean Russian aircraft being shot from the sky, could aggravate the ongoing war in Europe.

The invasion of Ukraine began on February 24 and is going into its eleventh day.

Filippo Grandi, the head of the U.N. refugee agency, told Reuters on Saturday it is the “fastest moving refugee crisis we have seen in Europe since the end of World War II.”

Mr Grandi said the number of people fleeing Ukraine could climb to 1.5 million by the end of this weekend.

A UNHCR data portal, launched on Wednesday, is keeping track of arrivals.