CNOOC, which regularly buys and trades Russian oil, has also cut back on March-loading volumes, traders said. PetroChina and CNOOC did not respond to requests for comment. In addition to seaborne imports, PetroChina continued lifting 800,000-900,000 bpd of Russian oil, mostly ESPO grade, via pipelines from Siberian fields under a long-term agreement. Sinopec, Asia's top crude buyer, has been filling in the gap on Russian imports with cargoes from West Africa, the Middle East and Brazil, traders said. (Reporting by Chen Aizhu and Florence Tan; Additional reporting by Reuters reporters in Moscow; Editing by Tony Munroe and Muralikumar Anantharaman) By Chen Aizhu and Florence Tan