Russia's Eurasia Drilling said on Monday it had agreed to extend a deadline on a proposed deal to sell a stake to international oilfield services firm Schlumberger from March 31 to April 30.

Last month, Schlumberger said it planned to buy a 45.65 percent stake in Eurasia for about $1.7 billion, potentially paving the way for it to become the sole owner of Russia's most active oilfield services company.

Eurasia Drilling said on Monday it was continuing to work with Russia's Federal Anti-Monopoly Service and Commission on Foreign Investment on the deal.

Russian officials are yet to grant the approvals needed for the deal to be completed.