MOSCOW/ATHENS/LONDON: Three Greek-managed oil tankers were hit by unidentified drones in the Black Sea on Tuesday as they were on their way to load crude at a terminal on Russia’s coast that serves as the main export point for Kazakh oil, sources told Reuters. The attacks come as Kazakhstan’s output cratered in early January with the US oil majors that dominate its oil sector struggling to pipe crude via Russia due to winter storms and infrastructure damage caused by an earlier Ukrainian drone attack. Kyiv has been targeting Russian energy infrastructure to pressure Moscow to end its war in Ukraine. It was not immediately clear, however, who was behind Tuesday’s tanker strikes. Ukraine’s government did not comment on the attacks. The Caspian Pipeline Consortium, which operates the terminal where the tankers were due to take on board cargoes, declined to comment. Shareholders in CPC’s 1,500-km (930-mile) pipeline include Kazakhstan’s state-owned oil company KazMunayGas, Russia’s Lukoil and units of US oil giants Chevron and ExxonMobil. Chevron said it was aware of reports of incidents involving vessels inbound to CPC loading facilities, including one Chevron-chartered tanker. “All crew are safe, and the vessel remains stable. It is proceeding to a safe port, and we are coordinating with the ship operator and relevant authorities,” it said. Two Suezmax tankers and one Aframax tanker were hit on their way to the Yuzhnaya Ozereyevka terminal, a loading point for around 80 percent of Kazakh crude destined for international markets, according to eight sources, who spoke to Reuters on condition of anonymity due to the sensitivity of the situation. The terminal itself had previously come under attack on November 29, when a Ukrainian drone hit one of three main CPC moorings at the facility, located near the port of Novorossyisk. Oil and gas condensate output in Kazakhstan plunged by 35 percent between January 1 and January 12 compared to December’s average, a source familiar with the data told Reuters, adding that the drop was mainly due to export constraints via the terminal. Kazakhstan’s energy ministry said on Tuesday that CPC was continuing to export oil via one mooring. Attacks on tankers in the Black Sea could increase both shipping and insurance costs for those seeking to load oil at Russian terminals on the Black Sea, which handle more than 2 percent of global crude. One of the tankers attacked on Tuesday, the Delta Harmony, is managed by Greece’s Delta Tankers, LSEG data showed. According to the sources, it was expected to load Kazakh-produced oil from Tengizchevroil, a unit of US oil major Chevron.