French prosecutors have charged a French IT company that allegedly helped the regime of Libyan leader Muammar Gaddafi spy on opposition figures who were later detained and tortured, sources close to the inquiry said Thursday.

Amesys, which is now owned by the Bull technology group, and its former chief, Philippe Vannier, were charged with complicity in acts of torture on June 18, the sources said.

The inquiry was opened in 2013 after a complaint by two French-based NGOs, the International Federation of Human Rights (FIDH) and the League of Human Rights (LDH).

They accused Amesys of selling internet surveillance gear to Libya between 2007 and 2011 which was used to hunt government opponents.

The deal was first reported by The Wall Street Journal in 2011, as the Arab Spring protests against autocratic governments raged in several Middle East countries, including Libya.

Contacted by AFP, a lawyer for the company, Olivier Baratelli, denied "any sort of complicity in torture whatsoever."

Amesys has acknowledged the tech deal with Libya, which was agreed in the context of a rapprochement between Gaddafi's regime and the West starting in 2007, when Gaddafi visited then French president Nicolas Sarkozy in Paris.

"A decade on, it's time to face justice," the FIDH said on Twitter.

London-based rights group Amnesty International welcomed the indictments of both firms as "unprecedented."

"These indictments send a clear message to surveillance companies that they are not above the law, and could face criminal accountability for their actions," Amnesty tech director Rasha Abdul Rahim said in a statement last week.