(Reuters) – U.S. oilfield service firm Halliburton (NYSE 🙂 Co warned Friday that Russia could seize its assets worth $340 million and impose future earnings penalties for its withdrawal.

Last month, the company announced that it would cease operations in Russia following the conflict with Ukraine. It announced Friday that the contracts would end on May 15 in compliance with U.S. sanctions.

It was not clear in the securities filing what the possible impairment charge would be. According to a securities filing, legal challenges and employees severance fees could increase any asset impairment. It already wrote down $22 millions on Ukraine assets.

Baker Hughes, a rival oilfield operator, said this week that Russia sanctions made their operations “significantly more complicated.” While it didn’t write down assets, the company said additional sanctions to Russia that could disrupt its Russian contracts would “could cause a material adverse affect” on future performance.