(Adds Sarkozy comments)
NOUAKCHOTT, Dec 24 (Reuters) - Gunmen armed with assault rifles shot dead four French tourists from the same family and seriously injured a fifth in Mauritania on Monday, local police and French officials said.
Members of the family were attacked in their car on the road 15 km from Aleg, in a popular sightseeing area 250 km (160 miles) southeast of the West African country's capital, Nouakchott, said a police officer who declined to be named.
The fifth tourist, the father of the family, was injured in the leg and taken to Aleg's hospital, and was in a serious condition, he said.
The three attackers were armed with semi-automatic assault rifles and drove two Mercedes saloon cars, he said.
French President Nicolas Sarkozy confirmed the deaths, but said details of the incident were still unclear and an investigation was under way.
"At the moment, it's still too early to say exactly what the reasons were for this attack which I can't describe because we don't know the motivation or even really how it occurred," he said during a visit to a hospital in Paris.
"As things stand, I can only confirm this sad news and offer my condolences," he said.
He said he would be speaking to Mauritanian President Sidi Mohamed Ould Cheikh Abdallahi soon.
There was no immediate indication whether Monday's attack had any political significance or if robbery could have been the main motive.
The assailants left the victims' car behind, but it was unclear whether any of their possessions had been taken.
It was the second fatal incident involving French tourists in Mauritania this month after two were killed when their hot air balloons burst as they were crossing a mountain range during a trip organised by a French adventure tourism company.
The former French colony spanning Arab and black Africa is generally peaceful, and even deposed veteran ruler Maaouya Ould Sid'Ahmed Taya in 2005 and installed democratic rule without a drop of blood being shed.
However, its eastern and northern reaches stretch deep into the Sahara, where thinly stretched security forces struggle to control armed smugglers trafficking drugs and weapons via ancient trading routes criss-crossing the vast desert.
Al Qaeda in the Islamic Maghreb, formerly known as the Salafist Group for Preaching and Combat and based in Algeria to the north, has long been linked to smuggling and extortion in Mauritania and Mali and Niger to the east.
Al Qaeda's second-in-command called in September for north Africa's Muslims to "cleanse" their land of Spaniards and French to restore "al-Andulus" -- the Arabic name for parts of the Iberian peninsula under Muslim rule at various times since the 8th century.
Mauritania borders Algeria and Morocco's breakaway region of Western Sahara in the north, both of which have been subject to armed rebellions, although Monday's attack took place far away in the south of the country near the border with Senegal. (Additional reporting by Firouz Sedarat in Dubai and James MacKenzie in Paris; writing by Alistair Thomson; Editing by Charles Dick)
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