Libya's deputy prime minister, Mustafa Abu Shagour (left), tweeted that the Mauritanian president, Mohamed Ould Abdel Aziz (right), had agreed to extradite Gaddafi's former spy chief to Libya. Photograph: Watt Abdel Jelill/AFP/Getty Images
Mauritania has agreed to extradite Muammar Gaddafi's former intelligence chief Abdullah al-Senussi to Libya, according to Libya's deputy prime minister.
"I have met the president of Mauritania and he agreed to the extradition of Senussi to Libya," Mustafa Abu Shagour wrote on Twitter.
The unconfirmed reports came as Libya, France and the international criminal court (ICC) in The Hague had appeared to be locked in a three-way tussle for custody of Gaddafi's brother-in-law, who was arrested in Mauritania on Saturday.
Earlier on Tuesday, a source in Mauritania told the Guardian that France – which is reported to have assisted in Senussi's capture – had alreadyreached an agreement over his extradition before he was arrested. They said the French had been pursuing Senussi for some time and were working with the Mauritanian authorities to plan his arrest at Nouakchott airport.
Senussi is wanted in France in absentia for a terrorist attack on a French airliner, which exploded over Niger in 1989, killing 170 people, including 54 French nationals. Although he has been convicted in absentia and sentenced to life imprisonment, experts say he would face a retrial if extradited to France.
Meanwhile, the Libyan National Transitional Council stepped up its efforts to place him on trial in Tripoli. A delegation led by Shagour, met Mauritania's president, Ould Abdel Aziz, on Tuesday morning, urging him to hand over the fugitive.
The third interested party, the ICC, said it may take legal action against France if the country – which is a fully fledged member of the court – sought to try him domestically rather than co-operating in his extradition to The Hague.
"If France seeks to extradite Senussi, or to have first national procedures before surrendering him to the court, that is a matter that would be debated before the judges. I cannot anticipate what their decision would be," Fadi el-Abdullah, spokesman for the court, told the Guardian. "There is a valid warrant of arrest against Senussi now, and we are asking for his surrender from Mauritania or from any other state."
Despite a formal request by the ICC for co-operation from Mauritania, the country had yet to respond, Abdullah said.
"The ICC has sent a request for co-operation and asking for conformation that Senussi has been arrested and for him to be surrendered to the ICC. We have not received any response to date. We remind Mauritania that although it is not a state party, it has been urged by UN Security Council Resolution 1970 to co-operate with the court on the Libya situation."
Further details have emerged regarding Senussi's arrest. Reportedly being held at the headquarters of Mauritania's security service in Nouakchott, Senussi was carrying a Malian passport that was obtained illegally, a source said.
"Senussi was not travelling on a fake passport, but an illegally obtained genuine one," the source said. "These are harder for border police to identify and are usually resolved through tipoffs, for example by intelligence services."