A former French hostage who was held captive by Islamist militants in Syria has claimed that he was tortured by the key suspect in the Jewish Museum shooting in Brussels.

Four people were shot dead in the attack at the museum in May this year. Two of the victims were Israeli tourists. A French female volunteer at the museum and a Belgian employee were also killed.

In an interview with Le Point magazine, Nicolas Henin who was among four journalists freed in April, described French jihadist Mehdi Nemmouche as a much feared terrorist who took pleasure in brutally torturing captives in Syria in 2013.

"When Nemmouche was not singing, he was torturing. He was part of a small group of Frenchmen whose visits would terrify the 50-odd Syrian prisoners held in the cells nearby," he said.

"Every night the blows would start raining down in the room, where I was also interrogated. The torture lasted all night, until dawn prayers."

Mr Henin, who was held for a period with American journalists James Foley and Steven Sotloff, both of whom were recently beheaded by the Islamic State group, described how he was personally targeted by Nemmouche and singled out for abuse.

"He looked at his hands, cracked his fingers like a boxer and adjusted his gloves," Mr Hénin said, adding Nemmouche used to ask him: "You see these motorbike gloves? I bought them to hit you. Only for you. Do you like them?"

Mr Henin's lawyer, Marie-Laure Ingouf, told Agence France-Presse that "all the hostages" confirmed Mr Nemmouche was one of the jailers.

"They lived alongside him for several months," she said.

Mr Nemmouche was arrested in France shortly after the attack on the Jewish museum and extradited to Belgium for questioning. He now in custody in Belgium awaiting trial on the charge of "murder in a terrorist context faces a hearing on his detention next week.

The French interior minister, Bernard Cazeneuve, said the information had been passed on to French judges. "This sinister character must be judged and he will be," Mr Cazeneuve said.