US President Joe Biden said Wednesday he believes Russia's potential use of chemical weapons in Ukraine is a "real threat."

"I think it’s a real threat," said Biden ahead of his departure for Europe when asked how high is the threat of chemical warfare right now.

Biden is scheduled to attend a NATO summit, EU leaders' gathering and G7 summit this week.

During his talks in Europe, Biden is expected to announce new US and allied sanctions on Russia in response to its ongoing war against Ukraine.

US National Security Advisor Jake Sullivan told reporters at the White House that Biden will announce the new economic penalties as part of a coordinated action with US partners and will further tighten existing sanctions to crack down on "evasion, and to ensure robust enforcement."

The Russia-Ukraine war, which began on Feb. 24, has met international outrage with the EU, US, and UK, among others, implementing tough financial sanctions on Moscow.

At least 953 civilians have been killed in Ukraine and 1,557 injured, according to UN estimates. It has warned, however, that the exact toll is likely much higher as it has not been able to gain access to areas of increased hostilities.

More than 3.6 million Ukrainians have fled to neighboring countries, according to the UN refugee agency./aa