Armed robbers held 25 people hostage at a bank in Naples for two hours on Thursday, before fleeing through a tunnel.

The three thieves entered a branch of Crédit Agricole in the southern Italian city at about 11.30am, taking hostage staff and customers, who were freed by police a couple of hours later.

“Thanks to the swift response … all the hostages were freed shortly after 1:30pm, without serious injuries,” Michele di Bari, prefect of Naples, said in a statement.

Emergency responders smashed windows to enter the bank in piazza Medaglie d’Oro in the city’s Arenella district, by which time the robbers had escaped, reportedly down a hole in the bank’s floor and into the sewers.

The company that manages Naples’s water network has been inspecting the sewer system, according to the local news site Fanpage.it.

It was unclear whether the robbers managed to flee with any loot. According to Fanpage, the robbers were believed to have targeted safety deposit boxes and there was no cash inside the bank.

The Naples prosecutor Nicola Gratteri was also at the scene.

One of the people held hostage, a bank customer, told Fanpage they had been locked in a room. “I was in the bank when they entered; there was definitely three of them. They came and locked us – customers, employees and the manager – in a room. They were armed but they didn’t use violence.”

A branch of Crédit Agricole in Milan was targeted in a similar robbery in 2020. In that case, two armed robbers walked into the premises through the main entrance and held staff hostage as two accomplices entered via a maintenance hole, having crawled through the sewer network. The gang stole several safe-deposit boxes before all escaping through the drains.