FILE PHOTO: The exterior of the Schlumberger Corporation headquarters building is pictured in the Galleria area of Houston, Texas, U.S., January 16, 2015. REUTERS/Richard Carson/File Photo

MOSCOW (Reuters) - Russia has given preliminary approval to a bid by U.S. oilfield services giant Schlumberger to acquire up to 49 percent of Russia’s Eurasia Drilling Co (EDC), an unexpected decision given a chilling in U.S.-Russian relations.

Washington has introduced a number of sanctions, including restrictions on financing for Russian companies over Moscow’s role in Ukraine’s crisis and alleged meddling in the U.S. 2016 presidential election.

RIA news agency cited Igor Artemyev, head of Russia’s anti-monopoly body (FAS), as saying the regulator would quickly start talks with Schlumberger, the largest oilfield services company by revenue.

“We (will) immediately start the talks with Schlumberger and hope that we are moving to the final stretch,” he was quoted by RIA as saying after a Russian government meeting on foreign investments.

The FAS said later on Saturday that the government investment commission had decided to extend the time frame for examining the deal, but it was not immediately clear how long that could take.

Schlumberger had initially planned to buy 51 percent in EDC, but decided to scale down its bid. The deal has faced difficulties as relations between Russia and the United States have deteriorated.

This is a second attempt by Schlumberger to acquire Russia’s leading oilfield services provider. In 2015, Schlumberger agreed to buy 45.65 percent of EDC for $1.7 billion, but the deal fell through after the FAS repeatedly postponed its approval. Later that year, EDC delisted its shares on the London Stock Exchange.

For Schlumberger, the investment would mean access to the Russian oil market, one of the world’s largest, at a time of rising crude prices.