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LONDON/SINGAPORE, Oct 29 (Reuters) - Chinese oil trader Unipec has restarted using tankers owned by state-owned shipping group COSCO after the United States eased sanctions temporarily on the Chinese state-owned shipping group, trade sources said on Tuesday
In one of the biggest sanctions actions taken by the U.S. government since its crackdown on Iranian oil exports, Washington imposed sanctions on Chinese tanker companies in late September for alleged involvement in moving crude oil from Iran.
COSCO Shipping Tanker (Dalian), a subsidiary of China's state-owned shipping group COSCO, was one of the companies blacklisted.
This prompted Unipec, the trading arm of Asia's top oil refiner, Sinopec, to make replacement bookings for shipments from the Middle East Gulf, shipping sources told Reuters in September.
Concern over shippers falling foul of the U.S. sanctions sent oil freight costs to record highs around the world, adding millions of dollars to the cost of every voyage.
Last week, Washington gave temporary approval for companies to wind down transactions with the designated COSCO subsidiaries.
A notice from the U.S. Treasury allowed for the "maintenance or wind down of transactions" including offloading non-Iranian crude oil involving the COSCO subsidiary until Dec. 20.
One of the trade sources said the U.S. had held consultations with industry officials and had allowed for the issuance of general licences which would permit new chartering activity with COSCO tankers.
It was unclear if this only applied to tankers that were not operated by the blacklisted COSCO entities.
U.S. officials could not be immediately reached for comment.
Refinitiv data on Tuesday showed one COSCO owned tanker Xin Pu Yang - owned by a subsidiary not affected by the U.S. sanctions - was sailing to Asia with a cargo of oil chartered by Unipec.
A Sinopec spokesperson declined to comment.
Zhang Zheng, investor relations manager with COSCO Shipping Energy Transport, the parent company of COSCO Shipping Tanker Dalian, said he was not immediately aware of the latest development when asked for comment.
Data from shipping valuation company VesselsValue showed COSCO Shipping Tanker Dalian had 17 vessels in its fleet including four supertankers, which can each carry 2 million barrels of oil, and other smaller vessels.
The wider COSCO group, whose subsidiaries are not affected by U.S. sanctions, has a fleet of more than 100 oil tankers including nearly 40 other supertankers, the VesselsValue data showed.
A trading executive with a Chinese oil major told Reuters separately that Chinese firms, including Sinopec, were resuming the chartering COSCO tankers.
"Sinopec got scolded by the government for not being a very responsible and conscientious state-owned enterprise," the official said, referring to the halt in COSCO charters.
Shipping sources said last week that at least three other COSCO tankers which were unable discharge their oil due to U.S. sanctions, and chartered by other companies, were on their way to Asia. (Additional reporting by Timothy Gardner in Washington and Collin Eaton in Houston, editing by Jason Neely/Veronica Brown/Jane Merriman)