Two giant US oil field services companies, Halliburton and Schlumberger, have said they are suspending operations in Russia, in response to US sanctions over the invasion of Ukraine.

Halliburton said on Friday it had suspended future business in Russia in compliance with sanctions that prohibit transactions and work, including for certain state-owned Russian customers.

Halliburton said it would prioritize safety and reliability as it wound down its remaining operations in Russia.

Halliburton said it halted all shipments of specific sanctioned parts and products to Russia several weeks ago and had no active joint ventures there.

Schlumberger, like Halliburton based in Houston, Texas, said it immediately suspended investment and technology deployment to its Russia operations and would actively monitor a “dynamic” situation.

“Safety and security are at the core of who we are as a company and we urge a cessation of the conflict and a restoration of safety and security in the region,” the Schlumberger chief executive, Olivier Le Peuch, said in a statement.

Companies that remain in Russia are under increasing pressure to leave.

More than 400 US and other multinational firms have pulled out of Russia, either permanently or temporarily, according to Jeffrey Sonnenfeld, senior associate dean for executive programs at the Yale School of Management, who has publicized a list of corporate actions in Russia.

Oil companies ExxonMobil, Shell and BP, along with major tech companies like Dell and Facebook, were among the first to announce withdrawals or the suspension of operations. Many others, including McDonald’s, Starbucks and Estée Lauder, have followed. Around 30 companies remain.

The Ukrainian president, Volodymyr Zelenskiy, on Wednesday asked Congress to press US businesses still operating in Russia to leave, saying the Russian market is “flooded with our blood”.