SINGAPORE - DBS said that two ATMs at Bugis street may have been compromised in the recent spate of unauthorised bank withdrawals.

The bank's preliminary investigations also increasingly indicate that a card skimming operation may be responsible for the unauthorised ATM transactions which have hit around 400 DBS and POSB customers.

In an update late Friday afternoon, the bank said it has identified the specific periods when the Bugis ATMs were compromised.

As a precaution, it has de-activated the ATM and debit cards of customers who used the machines in that timeframe.

"These customers have been contacted and given the option of having their cards replaced on the spot at the branch, or couriered to them," DBS said.