By Marie-Louise Gumuchian and Vicky Buffery
TRIPOLI/PARIS (Reuters) - Libya said on Sunday it was sending a delegation to Mauritania to press for the extradition of Muammar Gaddafi's intelligence chief Abdallah al-Senussi and Interpol called for his handover to promote rule of law in the North African state.
Senussi, 62, the last significant Gaddafi associate on the run since the dictator's overthrow and death in a popular revolt last year, was arrested in the West African state after his arrival late on Friday on a flight from Morocco.
Senussi was being held at the headquarters of the Mauritania's security service in the capital Nouakchott, sources there said, and diplomatic sources said he was carrying several false passports when detained.
Despite support from Interpol, Libya's interim government may get embroiled in a legal tug-of-war with France and the International Criminal Court (ICC) over Senussi as they also want to put him on trial.
Senussi, who for decades inspired fear and hatred among many Libyans, is sought by the Hague-based ICC on charges of crimes against humanity over security force attacks on anti-Gaddafi protesters during the eight-month uprising.
Interpol, the international police organization based in Lyon, France, said it had issued a Red Notice for Senussi at Libya's behest requesting member states to arrest him, if found on their soil, for fraud offences including embezzling public funds and misuse of power for personal benefit.
A Libyan government spokesman said on Saturday Tripoli had sent a request for Senussi's handover through Interpol, while France had filed a competing extradition request, according to a presidential palace source.
Interpol previously circulated a Red Notice for Senussi at the ICC's request in September 2011 for crimes against humanity.
"Interpol has committed itself to supporting Libya's efforts to achieve its goal of rebuilding their country and being guided by the rule of law, and clearly their request for an Interpol Red Notice for Senussi is a clear demonstration of their commitment to international police cooperation and justice," the agency's chief Ronald Noble said in a statement.
"Targeting and arresting those involved in embezzling funds and making them accountable for their actions before the courts will help Libya achieve its goal," said Noble.
The Libyan interim authorities' struggle to bring rival militias - who were instrumental in Gaddafi's overthrow - and tribes under control has raised doubt about their ability to assure fair trials for old regime figures.
But Tripoli has insisted Senussi would get proper justice there, while France, confirming it played a role in his arrest in Mauritania, wants to try him for the 1989 bombing of an airliner over Niger in which 54 French nationals died.
LIBYAN MISSION TO MAURITANIA
Libyan foreign ministry spokesman Saad Elshlmani said the ministry was in touch with its Mauritanian counterpart, adding that a delegation would head for Mauritania, possibly including the deputy prime minister.
Asked when the delegation would go, Elshlmani said: "Soon".
France, which led Western backing for the insurgency that toppled Gaddafi with the help of NATO air strikes, said it had cooperated with Mauritanian authorities on the apprehension of Senussi ahead of its extradition request.
A statement from President Nicolas Sarkozy's office noted Senussi had been sentenced in absentia for the UTA airliner attack, in which 170 people were killed. Families of the victims immediately demanded he face justice in France.
An ICC spokesman said on Saturday an ICC arrest warrant for Senussi remained valid and requested that it be implemented.
The ICC has charged Senussi and Gaddafi's son Saif al-Islam, captured in the southern Libyan desert in November, as being "indirect co-perpetrators" of murder and persecution of Libyans who rose up against the veteran dictator.
But the Libyan foreign ministry's Elshlmani said: "He's a Libyan ... I think they will give us the priority. He will face justice. It is very important that he is sent to Libya."
Mauritania has not signed the Rome Statute governing the ICC and authorities were not immediately available to comment on what they would do with Senussi.
"They are not obliged to give him to the ICC because they are not members, so they will probably agree on our request but we will wait and see," Elshlmani said.
Senussi is also suspected in his North African homeland of having played a central role in the killing of more than 1,200 inmates at Tripoli's Abu Salim prison in 1996.
It was the arrest of a lawyer for victims' relatives that sparked Libya's Arab Spring revolt in February last year.
A security source in Nouakchott who spoke on condition of anonymity said Senussi was "currently on the premises of the Directorate General of Territorial Security located in the centre of Nouakchott, in the government district".
Diplomatic sources said Senussi had several passports in his possession including a false Malian passport with which he was arrested. They said the passports were under several aliases and some pictures showed Senussi with a beard.
The Mauritanian government has made no comment beyond a report by its official news agency which said Senussi was arrested at Nouakchott airport on a regular flight from Casablanca, carrying doctored Malian travel documents.
"Senussi appears to have used a false passport to get into Morocco ... It's puzzling for us but after all this is the head of intelligence of the Gaddafi regime and they had tremendous resources," a Moroccan foreign ministry source said.
Britain, along with France one of the key Western backers of the insurgency, also cited the need for Mauritania to cooperate with the ICC in a statement by Foreign Secretary William Hague.
(Additional reporting by Laurent Prieur in Nouakchott, Souhail Karam in Rabat and Roberta Cowan in Amsterdam; Editing by Mark Heinrich)