Rome, Nov 21 (IANS): Dozens of prison guards were under investigation, and at least 11 of them were under house arrest in Italy on Wednesday on suspicion of torture and abuse of power against prisoners, authorities said on Wednesday.

The operation was ordered by prosecutors in Trapani, Sicily region, at the end of a three-year-long probe triggered by inmates' reports about routine abuses and violence within the prison facility, Xinhua news agency reported.

Overall, 46 jail officers were being probed. Investigators obtained video footage that confirmed the prisoners' complaints, showing guards systematically beating and mistreating inmates in some isolated cells.

Addressing a press conference, Trapani chief prosecutor Gabriele Paci said violence against inmates was not episodic, but "became a sort of method to ensure order within the prison."

In early August, the Italian Parliament passed a law to improve jail life conditions, allowing inmates to make more phone calls, and streamlining rules to obtain early release or alternative measures to the prison.

By end of June, Italian jails hosted 61,480 prisoners out of a capacity of 51,234, the Justice Ministry said. No plan to build new facilities has been announced so far.