The Russian government missed the deadline on Jan. 15 for paying $50 billion to the shareholders of defunct oil company Yukos in what has been called the largest commercial lawsuit in history.

Yukos’ shareholders are planning to seek seizure of Russian government assets abroad as payment for the debt, dealing yet another blow to the Kremlin amid an economic and financial crisis. The lawsuit, along with falling oil prices and a plummeting ruble, could make it harder for the Kremlin to finance its ongoing war against Ukraine.