ROME (Reuters) - Europe’s top human rights organization asked Italy for more information on its work intercepting migrants at sea, warning that any moves to return them to Libya would break international treaties.

The Council of Europe said on Wednesday it had written to the Italian government a day after an Italian navy ship helped Libya’s coastguard as it headed off 228 migrants. The coastguard later brought the refugees back to Libya.

Italy would break the European Convention on Human Rights if it had a direct role in returning migrants to Libya, where they face “a real risk of torture or inhuman or degrading treatment or punishment,” the Council’s human rights commissioner, Nils Muiznieks wrote.

Italy’s interior minister, Marco Minniti, told Ansa news agency the country’s ships had never returned migrants to Libya after a rescue.

“Italy’s activities are aimed at training, equipping and giving logistical support to the Libyan coast guard, not in returns,” he added.

Andrea Doria destroyer provided a Libyan coast guard vessel with life-jackets as it took migrants off of two rubber boats on Sept. 27, according to Italy’s navy.

The coastguard later posted pictures online of it bringing the migrants back to Libya, and said they were taken to detention centers. The United Nations has condemned Libyan detention centers as “inhuman” because of abuse and a lack of basic hygiene, medical care and even food.

The Council of Europe said on Wednesday Muiznieks wrote to Minniti on Sept. 28.

Italy and the European Union have provided training, equipment, repairs and vessels to the Libyan coastguard in an effort to bolster its ability to stop to the departure of overcrowded migrant boats.

More than 600,000 migrants have set out for Europe from Libya since 2014. With Italy facing an election early next year, Minniti has spearheaded efforts to try to provide money and equipment to Libyan authorities that agree to fight people smuggling.

Sea arrivals to Italy have fallen 25 percent this year over the same period of 2016 as the Libyan coast guard working in tandem with an armed group west of Tripoli clamped down on departures. Departures from east of Tripoli and from Tunisia, however, are now on the increase.