SHANGHAI - Chinese e-commerce giant Alibaba assisted police in busting more than 1,400 counterfeit production sites, leading to the arrest of 880 suspects last year, according to a report issued Friday.

The cases involved more than 3 billion yuan ($435 million), double the amount in 2015, said the report.

As of last year, Alibaba was cooperating with more than 18,000 international brands on the anti-counterfeit initiative.

Counterfeiting in cross-border trade has become a new front for the initiative, as approximately 30,000 cross-border sellers were purged by Alibaba from its platforms with the help of big data technology from February 2016 to the end of last month.

"Traditionally, counterfeiters produce in China and sell overseas, but now they are apt to produce abroad and sell domestically," said Zheng Junfang, chief platform governance officer of Alibaba.

One typical case, in which lubricating oil labeled under famous brand names, such as Shell, was bottled in Malaysia and sold in China, was solved with the intervention of the Malaysian government.

"The outcome was hard won," Zheng said, adding that crackdowns on cross-border counterfeiting are difficult given complicated law enforcement issues in different countries.

Despite Alibaba's continuous efforts to cleanse its platforms of fake goods, its customer-to-customer marketplace, Taobao.com, returned to the US trade representative's blacklist of "notorious marketplaces" known for sale of counterfeit goods and violations of intellectual property rights in December 2016. Taobao was first put on the blacklist in 2011 but removed in 2012 after effective rectification.