* Areva firm, France urge people to quit danger zones
* French foreign ministry suspects al Qaeda, no claim made
* Hostage takers move captives to Mali - French radio
(Adds Mauritanian source on military operation, paragraph 6)
By John Irish
PARIS, Sept 17 (Reuters) - France urged its nationals on Friday to quit danger zones in Niger after saying it suspected an al Qaeda group of kidnapping seven foreigners in the country, including five French citizens.
The Foreign Ministry issued the warning to French nationals after Foreign Minister Bernard Kouchner accused al Qaeda's North African wing (AQIM) of the abductions, although there has been no claim of responsibility.
Niger's military was searching for the hostages and an officer told Reuters that pilots in light aircraft had spotted three vehicles travelling at high speed through the Tamesna region towards the Malian border.
The hostage takers and their abductees were seen travelling across the border from Niger into the desert of Mali, French public radio reported, citing security sources.
A spokesman at the French Foreign Ministry declined to confirm that report and said France had still not received any demands from the hostage takers a day after the kidnapping.
Separately, a Mauritanian government source said Mauritanian soldiers had clashed with forces identified as belonging to AQIM in the desert region between the two countries. However, no other details were available and it was not clear whether there was a link to the hostage situation.
Thursday's abductions, which included a French employee of nuclear firm Areva and his wife, are likely to raise questions about security for workers in the uranium mining region, where groups linked to AQIM operate.
"There is a red (danger) zone. We are asking all those in it to leave," Foreign Ministry spokesman Bernard Valero said. "Citizens that were in Arlit are heading back to Niamey."
Valero said France had about 1,700 of its citizens living in Niger with dozens operating in the red zones.
An Areva executive, who asked not to be identified, confirmed that the company had called some of its staff back from Arlit, where the kidnapping took place.
"We suspect it's the same groups ... linked to the mainstream of AQIM," Kouchner told Europe 1 radio on Friday. "Unfortunately, we have dealt with them before."
Kouchner said there was "no certainty" as there had yet to be a claim of responsibility.
Security experts say AQIM is exploiting the Sahara desert's empty expanses and porous borders to kidnap Westerners and also create a safe haven from which it could, in the future, launch attacks on Western targets.
Two other people kidnapped on Thursday were citizens of Madagascar and Togo, according to the Nigerien government.
President Nicolas Sarkozy held emergency security talks with the prime minister, interior minister and armed forces chief to decide what measures France would take.
France has said it is at war with the group and pledged further military support to countries in the region after Islamists said in July they had executed a French citizen they were holding when a French-Mauritanian raid failed to free him.
The Areva executive said the kidnappers travelled in four-wheel-drive vehicles to two houses where the foreign employees resided.
"They overpowered the civilian guards at the villa before waking up the occupants, who were all French. They took them with them. They did the same at the second villa and then left the town," he said.
A Niger government spokesman said a local Areva employee had been forced to guide the kidnappers to the right houses. He was then taken hostage too but released about 10 km (6 miles) out of town. (Additional reporting by Nick Vinocur, Tiemoko Diallo in Niger and Abdoulaye Massalatchi in Mali and Laurent Prieur in Nouakchott; editing by Brian Love and Ralph Boulton)
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