China has investigated more than 6,700 cases of bank card related crimes in the first four months this year, and 4,800 cases have been solved, the Ministry of Public Security (MPS) announced Friday.

Measures had been taken to crack various bank card related crime cases including fraud using fake cards, malicious overdraft and illegal withdrawal from credit cards, Zhang Tao, an official with the MPS's Economic Crime Investigation Department, told a press conference.

The MPS launched a nationwide crackdown on such crimes jointly with the People's Bank of China, China's central bank, in January, Zhang said.

The campaign will last till October.

The MPS was taking specific steps to prevent bank card related crimes during the Shanghai World Expo, Zhang said.

Due to the use of new technologies, it has become increasingly difficult to catch criminals committing bank card related crimes, Zhang added.

The MPS had also solved 1,700 cases of invoice related crimes, such as making or selling fake invoices, and confiscated 87 million fake invoices so far this year, Zhang said.

Crackdowns on counterfeiting had also been effective with some 330 cases solved and fake money with the face value of 151 million yuan (about 22 million U.S. dollars) confiscated, Zhang said.