The operation, which saw customs officers from the port city of Ningbo join forces with local law enforcement and maritime police, spanned eight Chinese regions, including the coastal provinces of Zhejiang, Jiangsu, Shandong and Fujian.
Customs authorities described the swoop as "one of the most extensive operations" to combat refined oil smuggling along China's southeast coast in recent years, in terms of area.
The deal calls for up to 10 million tonnes of oil products shipments, split over three years, from March, and is part of a show of support for Minsk from Moscow following last year's presidential election.
Latvian ports of Riga and Ventspils are projected to get up to 111,000 tonnes of gasoline produced at the Mozyr refinery, an increase from 74,000 tonnes set for February.
The three Baltic nations imposed sanctions on Lukashenko and his allies following the elections and he promised to re-route oil products shipments to Russian ports in retaliation.
Shipments, set to start from March, would rise to 3.2 million tonnes next year and stay at 3.1 million tonnes in 2023.