By Lili Bayer, Julia Payne and Anna Hirtenstein BRUSSELS, Dec 15 (Reuters) - The European Union adopted fresh sanctions against Russian oil interests on Monday, targeting traders Murtaza Lakhani and Etibar Eyyub for helping Moscow to circumvent Western sanctions on crude exports that help to fund Russia's war in Ukraine.

The Kremlin has turned the threats into action.

Oil revenue is a key part of Russia's economy, allowing President Vladimir Putin to pour money into the war effort against Ukraine without worsening inflation for everyday people and avoiding a currency collapse.

The U.S. has agreed to provide unspecified security guarantees to Ukraine as part of a peace deal to end Russia's nearly four-year war, and more talks are likely this weekend, U.S. officials said Monday following the latest discussions with Ukrainian President Volodymyr Zelenskyy in Berlin.

Russia’s Central Bank says it has filed a lawsuit against Belgian financial institution Euroclear. That's the Brussels-based clearing house that holds most of Moscow’s frozen assets in Europe.

Leaders of eight easternmost European Union nations called on the bloc to treat the defense of its border regions as a priority in the face of an aggressive Russia and to unleash funding.

Most people outside of banking won't have heard of Euroclear. It's a Brussels-based settlement provider that enables the transfer of ownership of securities between seller and buyer. The firm is the focal point of a major geopolitical confrontation between Russia and the European Union.

Imports dipped after the invasion, and Europe placed sanctions on a number of executives at Russian fertiliser companies. But it soon made clear that the companies themselves, and the commodities they sell,

The European Union has implemented new sanctions against individuals and entities involved in Russia's “shadow fleet” of oil tankers, part of its ongoing response to the Ukraine invasion.

European Union nations that face Russia and its ally Belarus on NATO's eastern flank called for the EU to take a bigger role in enhancing the continent's defence and security, the leaders of eight countries said as they met in Helsinki on Tuesday.