Twenty-four people were hospitalized, including at least one in a critical state, after an accident at an underground escalator in central Rome on Tuesday.

Shortly after 7.30 pm (1730 GMT), a crowded escalator at Repubblica station, near the Termini train station, picked up speed suddenly, sending people crashing down to the foot of the stairs.

A spokesman for Italy's civil protection agency gave the figure for the hospitalized as 24, adding that more than one of them was a "code red," meaning that they were seriously hurt.

The victims were mostly Russian nationals thought to be fans of CSKA Moscow who travelled to Rome for a Champions League match with home side Roma, but among them were also Italians, the Rome Prefecture said.

The Russian Embassy in Italy said that 15 Russian and four Ukrainian nationals had been hospitalized, TASS reported early Wednesday.

Most of the victims suffered light leg injuries, but one risks a foot amputation, the ANSA news agency said.

"The thoughts of everyone at AS Roma are with the football fans and members of the public who were injured when an escalator collapsed in a subway station in Rome on Tuesday evening," the Italian football club said on Twitter.

Rome Mayor Virginia Raggi, told reporters on the scene of the accident that according to witness accounts, fans were "jumping and dancing" on the escalator before it broke down.

"It was a strange accident," Rome firefighters' commander Giampiero Boscaino was quoted as saying by ANSA, adding that it was too early to speculate about what caused it.

Prosecutors and local transport company ATAC announced separate investigations, and ANSA reported that the metro station had been sealed off by police.

In a separate incident near the Olimpico stadium, a CSKA Moscow supporter suffered knife wounds in clashes with Roma fans before the start of the game, which kicked off on schedule at 9pm.