Oil prices strengthened on Monday as an attack on an oil pipeline pumping station in the Caspian Sea slowed flows from Kazakhstan, while investors monitored developments of a possible Moscow-Kiev ceasefire agreement that could ease sanctions and increase global supplies.

A top Russian official has blamed Ukraine for a recent drone attack on a Russian pipeline, arguing that the attack targets U.S. oil companies and aims to destabilize the global oil market.

However, CPC, is subject to Russian law, since the pipeline crosses Russian territory, carrying about 2m barrels per day of crude from Kazakhstan’s Tengiz field on the northeastern shore of the Caspian to the Black Sea port of Novorossiysk, from where it is shipped to international markets.