BEIJING: Russia remained China's largest crude oil supplier in January, with imports rising 25 percent year on year to hold off rival Saudi Arabia, Chinese customs data showed on Monday.

Imports from Russia - China's top supplier for the past three years - stood at 6.97 million tonnes, or 1.64 million barrels per day (bpd) last month, compared with 1.31 million bpd in January last year and 1.66 million bpd in December, according to Reuters calculations based on data from the General Administration of Customs.

Saudi Arabia supplied 5.76 million tonnes, or 1.36 million bpd, in January, up 34.2 percent from a year ago.

Saudi state giant Aramco signed preliminary deals in Beijing last week to invest in two greenfield refineries, pushing to recoup lost market share in the world's largest oil importer.

Shipments from Venezuela were 1.74 million tonnes, or 409,260 bpd, up from 1.153 million tonnes in December.

The United States started to impose fresh sanctions on Venezuela in January aimed at cutting off oil revenues and forcing President Nicolas Maduro to step down.

China, Venezula's top financier, has been maximizing oil loadings from the South American exporter in January and February, taking about 8-10 million barrels as loan repayments, said Chinese traders involved in the programme.

Imports from Iran were 1.6 million tonnes, or 377,038 bpd, versus 504,000 bpd in December. That compared with 360,000 bpd allowed under the U.S. sanction waiver that lasts until May.

U.S. shipments to China, which have been hit by a trade war between the two nations, were at zero for a second month in a row. Imports for 2018 were up 24.8 percent from 2017 at 245,616 bpd.