ExxonMobil has halted drilling on its platform in the Kara Sea and begun shutting down its $700-million joint venture with Russia's Rosneft energy giant to comply with U.S. sanctions that take effect next week, energy industry sources reported Friday. The drilling operation on the U.S. oil company's platform off Russia's far-north Yamal peninsula was meant to begin tapping an estimated 9 billion cubic meters of oil under the sea worth $885 billion at current prices, Bloomberg reported. The business information conglomerate cited three unidentified oil industry sources as saying a day earlier that ExxonMobil had already ceased drilling in preparation for installing at least a temporary seal on the exploratory well. ExxonMobil has been granted a license by the U.S. Treasury Department to "enable the safe and responsible winding down of operations related to this exploration well," the Irving, Texas-based company said in a news release posted on its website Friday. It said ExxonMobil was "complying with all U.S. sanctions."