French anti-terror prosecutors have opened a preliminary inquiry into torture and acts of barbarism allegedly committed by Emirati Gen. Ahmed Nasser al-Raisi, who in November became president of Interpol, judicial sources said Thursday.

The probe follows a legal complaint by a nongovernment organization (NGO) that accused al-Raisi of being responsible for the torture of an opposition figure in his role as a high-ranking official at the United Arab Emirates (UAE) Interior Ministry.

The Gulf Centre for Human rights (GCHR), holding al-Raisi responsible for the inhumane treatment of Ahmed Mansoor, an opponent of the Emirati government, lodged its complaint in January with the anti-terror prosecutors unit whose brief includes handling crimes against humanity.

Allegations of torture had already been leveled at al-Raisi by human rights organizations when he ran for president of Interpol, saying they feared the agency would be at risk of exploitation by repressive regimes.

He was nevertheless voted in as president in November following generous funding from the UAE for the Lyon, France-based body.

There were also accusations that Abu Dhabi had abused Interpol's system of so-called "Red Notices" for wanted suspects to persecute political dissidents.

The probe against al-Raisi is being handled by the prosecution unit for crimes against humanity, genocide and war crimes, the sources said.

William Bourdon, a high-profile lawyer acting for the GCHR, said it was "totally incomprehensible" that the prosecutors had not immediately ordered al-Raisi's arrest which, he said, "they should have done given that he is in France."

The accusations were a sufficient motive to lift Raisa's diplomatic immunity which he enjoys thanks to an agreement between the French state and Interpol, Bourdon said.

GCHR boss Khalid Ibrahim told Agence France-Presse (AFP) he had been interviewed by French police on March 18.

"I told them the French Prosecutor is very slow in taking actions in relation to ... very serious allegations of torture against Maj. Gen. Ahmed Naser al-Raisi," he said.

Two previous complaints against al-Raisi had been rejected on competency grounds by French prosecutors who said they could not prosecute unless the accused resided in France permanently or temporarily.

But in its latest filing, the NGO was able to show that al-Raisi was in Lyon in January and again in March, using his activity on Twitter as evidence.

Al-Raisi was elected following three rounds of voting during which he received 68.9% of votes cast by Interpol member countries.

His four-year role at Interpol is largely ceremonial, with Secretary-General Juergen Stock handling the day-to-day management of the organization.