Three men dressed as gladiators and Roman soldiers have been arrested by police in Rome for allegedly exhorting money from tourists after posing for souvenir selfies near the city's famous Colosseum.

The suspects offered tourists the chance to take photos with them at the famous site. Afterward, they demanded up to 500 euros ($521) as payment, the police said on Saturday.

Sometimes they allegedly threatened people to get the money.

The public prosecutor's office placed two of them under house arrest, while one was remanded in custody.

Several foreign tourists filed complaints between August and September this year, the police said.

One visitor from Ireland told the men he had no money after being photographed. The men then allegedly forced him to withdraw money from a cash machine.

When he returned with 200 euros, they allegedly sent him out again to get another 50 euros.

An Italian tourist was asked for 40 euros but refused to pay. The suspects then surrounded him and threatened to hurt him, eventually extorting 150 euros from the man.