TAIPEI - Taiwan's top eight banks have suspended services on 900 Automated Teller Machines(ATMs) across the island, after thieves made off with NT$70 million (S$2.94 million) in a coordinated heist, apparently with the help of malware.

Bank of Taiwan, Chang Hwa Bank, First Bank and five other banks said on Tuesday (July 12) they were checking their German-made cash machines after First Bank's ATM machines in Taipei and Taichung were broken into last weekend.

First Bank Vice President Yeh Chung-huei told reporters the money was stolen from 34 ATMs at 20 of the bank's branches in the two cities on Saturday and Sunday.

He said malware is believed to have been installed into individual ATMs, making the machines dispense bills automatically.

Police are hunting for three men, identified as Russians, who were captured on surveillance camera withdrawing the money. Two of the suspects are believed to have left Taiwan on Monday (July 11).

Police believe that people from the bank could also have been involved in the heist. They said if the ATM machines are confirmed to have been tampered with malware, the theft would be the first case of its kind in Taiwan.

Taiwan's Central News Agency said the bank's surveillance video showed two unidentified men in hats and masks getting ATM machines to dispense a large amount of bills.

The suspects then dumped the bills into their backpacks and left quickly, it added.

The bank first discovered the scam after finding irregularities in its accounts on Monday. It promptly informed the Financial Supervisory Commission.

Mr Yeh said none of its customers has been affected by the robbery and their interests will be fully protected.

Nonetheless, it was running checks on its cash machines made by German retail banking hardware provider Wincor Nixdorf. The case also prompted the other banks to do their own checks.

The ATM services are expected to resume on Wednesday.