Eight banks in Taiwan have suspended services on 900 Automated Teller Machines (ATMs) after thieves managed to steal NT$70 million, or US$2.17 million, from ATMs over the weekend in a coordinated heist that involved use of a malware.

Taiwan's First Bank said that the thieves stole the money using malware from 34 ATMs at 20 branches located in the country's capital city Taipei and Taichung.

On Tuesday, Bank of Taiwan, First Bank and Chang Hwa Bank, along with five other banks said that they are now checking cash machines after First Bank's ATM machines were broken into on Saturday and Sunday.

First Bank Vice President Yeh Chung-huei said that a malware may have been installed into each of the ATMs, making it possible for the machines to dispense money automatically.

Police are currently on the hunt for three men identified as Russians who were seen on surveillance video withdrawing money. The video showed men in hats and masks getting into the machines to withdraw large amount of bills.

After getting the bills, the suspects placed the money in their backpacks and left quickly. Two of the suspects are believed to have already left the country on Monday.

Authorities said that if malware is proven to have been installed in the machines, it would be the first theft of its kind in the country. Cybercriminals, however, have long been known to use malware to steal or extort money.

Police also consider the idea that people from the bank may have also been involved in the heist. The bank first learned about the scam on Monday after they noticed accounts irregularities. The bank then informed the Financial Supervisory Commission.

Yeh said that none of its customers has been affected by the theft, and their interests will be protected. The bank, however, is conducting checks on the German-made cash machines. The incident also prompted other banks to conduct their own checks.

Financial Supervisory Commission (FSC) Vice Chairman Kuei Hsien-nung said that First Bank needs to explain the incident quickly to the public. The bank would also bear full responsibility for the amount that was stolen from its machines.

Taiwan's top financial regulator also asked the bank to conduct an overall review of its internal control so similar incidents would not happen again in the future.

Kuei said that investigation by an information security agency would determine if there was lapse on First Bank's management.