Belarus has also been banned from IBU World Cup and Cup events with its athletes only eligible to take part as neutrals.

Both countries' flags and anthems have also been banned.

The IBU confirmed that it would follow recommendations from the International Olympic Committee (IOC) "to ensure that the national symbols of Russia and Belarus are not present at IBU events".

In response, the RBU withdrew from the remainder of this season's events, claiming that the decision to force its athletes to compete as neutrals was "unlawful, unreasonable and categorically unacceptable".

It had vowed to challenge the decision in court, and Russian state news agency TASS reported that it intends to take its case to CAS.

The Biathlon Federation of Belarus has also pulled out of the final three World Cups of the season.

A meeting of the IBU Executive Board had ruled that Russia and Belarus' flags would be replaced by the IBU flag, with symbols and national emblems also banned from venues, including on team uniforms.

Anthems of both countries were also prohibited at IBU events, while neutral athletes' results would not contribute to the Nations Cup or Relay points totals.

Russia are currently top of the women's Nations Cup standings and second in the men's.

The Russian Olympic Committee won four biathlon medals at the Beijing 2022 Winter Olympics, with Belarus clinching one.

The IBU opted to allow the World Cup in Otepää from March 10 to 13 to go ahead as planned with the Estonian Government banning Russian and Belarusian teams, and confirmed that this would also be the case should other host nations introduce similar measures.

The Biathlon Federation of Ukraine has pulled out of remaining IBU World Cup and Cup events this season, but the International Federation added that it has "offered practical support to the Ukrainian biathlon family" and that the country's flag will be raised during competitions.

"The IBU strongly condemns the Russian attacks on Ukraine and expresses its deepest sympathies for all those affected," it said.

"Ukraine is a country with a great biathlon tradition and fanbase and the IBU stands in solidarity with them.

"We sincerely hope a peaceful resolution can be found to put an end to the current conflict and suffering."

The RBU was relegated to provisional membership of the IBU in December 2017 following he Russian doping scandal at the Sochi 2014 Winter Olympics and was required to meet 12 conditions for reinstatement.

A working group overseeing its reinstatement confirmed that the RBU will not be eligible to become a full member again until at least December 2022, with the Russian Anti-Doping Agency being declared compliant with the World Anti-Doping Code as one of the criteria.

Russia's attack on Ukraine has been widely condemned.

Along with its ally Belarus, Russia has been hit by sporting sanctions, with the IOC insisting both countries should be stripped of sporting events which have not already been moved.

Hundreds have been killed in the conflict and many thousands more displaced.

Russian forces have entered Ukraine's second city Kharkiv, while an oil depot near the capital Kyiv was bombed overnight.

Ukraine's President Volodymyr Zelensky has imposed martial law and urged citizens to take up arms to fight the invasion.