BEIJING -- Chinese police have arrested some 1.15 million suspects linked to over one million drug-related crimes since 2005, the National Narcotics Control Commission (NNCC) said Sunday.

Over 751 tonnes of drugs were seized in the period, it said.

In 2015 alone, some 38,900 suspects were arrested for trafficking illegal drugs to overseas, the NNCC said.

China has witnessed ballooning drug problems for years. Earlier reports said China had 3.23 million registered drug users as of July 2015, of which almost 60 percent were aged 35 or younger.

According to the NNCC, to counter the problem, China has signed 24 inter-governmental documents with over 20 countries in recent years to step up drug control cooperation.