Police in Italy have been left embarrassed after thieves robbed a bank despite warnings from local residents that they could hear a tunnel being dug, according to media reports.

The four robbers dug the tunnel under a bank in central Milan, and once inside waited for the first employees to arrive before forcing them to open the safe and empty the safety deposit boxes.

Police arrived on the scene after the alarm went off, only to discover that the crooks had made their escape.

Local residents were quick to point out that they had warned the authorities something odd was going on underneath the building.

“We began hearing noises on Sunday evening. We were jokingly saying to each other, ‘Are they robbing the bank?’,” one unnamed resident was quoted as saying in the media.

“On Monday one of us went to the bank to warn them about the tremors we had felt. Others went to the nearest police station on Tuesday because the sounds had not stopped.”

On Thursday, the night before the robbery, “even the pavement outside was shaking”, they added.

The value of the theft was not immediately known.