Planned Western sanctions against Russia over the country's attack on Ukraine are weighing on European financials.

The European Stoxx bank index collapsed by up to 8.7 percent on Thursday.

The shares of the Austrian Raiffeisen Bank International (RBI), which is particularly heavily involved in Russia, showed the highest price losses of more than 20 percent.

The Italian Unicredit and the French Société Générale also have larger subsidiaries there.

Unicredit fell more than 12 percent, while Société Générale shares lost around 11 percent.

The EU wants to freeze Russian foreign assets and block the country's banks from accessing European financial markets.

Some institutes such as Deutsche Bank referred to their emergency plans.

Raiffeisen Bank emphasized that its banks in Russia and Ukraine are well capitalized.

In addition, provisions were made last year and hedging was increased against exchange rate fluctuations in the Russian ruble and the Ukrainian hryvnia.

For the Austrian bank, Russia is by far the most important single market, which recently made a net profit of EUR 474 million.

German banks have 6 billion euros on fire

RBI's total exposure in Russia amounts to EUR 22.85 billion.

With a market share of 2 percent, RBI is a very small bank compared to the Russian institutions.

The two major German banks also fell under the wheels, although they no longer have any significant business in Russia.

The shares of Deutsche Bank and Commerzbank each lost around 10 percent in trading.

"We have prepared for various scenarios and developed contingency plans," said a spokesman for Deutsche Bank. "We have significantly reduced our exposure to Russia in recent years and our risks are under control."

Commerzbank explained: "We are prepared for various escalation scenarios." The commitment in Russia and Ukraine is manageable, it has been significantly reduced in recent years. According to a group spokesman, Commerzbank has 135 employees in Russia and one employee in Ukraine According to Bundesbank figures, the claims of German banks against Russia total a good 6 billion euros.The Association of German Banks (BdB) pointed out that most financial institutions "due to the sanctions that have been in place since 2014 with their involvement in Russia held back for the last few years".