Al—Qaeda in the Islamic Maghreb (AQIM) has claimed responsibility for the abduction in Niger of seven foreign workers, five of them French.

In an audio message broadcast by al—Jazeera late Tuesday, a man claiming to be Salah Abi Mohammed, a spokesman for al—Qaeda’s North African affiliate, said an Algerian member of AQIM led the operation on a uranium mine on Thursday.

“In announcing our claim for this operation, we inform the French government that the mujahedin will later transmit their legitimate demands,” he said. “We also warn [the French government] against any sort of stupidity.” An estimated 80 French soldiers have set up a base in Niger’s capital, Niamey, and French planes were conducting an air search over the desert for the kidnapping victims.

The French nuclear energy firm Areva SA employs two of the French nationals, both of whom worked at the uranium mine near Arlit in northern Niger.

The other three French nationals, a Togolese citizen and an employee from Madagascar worked for the French construction firm Sogea Satom, a subcontractor at the Areva mine.

The daily Le Monde reported on its website that the hostages were likely being held in north—eastern Mali, in a mountainous region near the border with Algeria.

French Interior Minister Brice Hortefeux said in the Malian capital Bamako that the kidnappers had “very probably crossed the border of Niger to be in Mali.” Mr. Hortefeux was in Mali to take part in the celebration of the 50th anniversary of the country’s independence. He is expected to use the occasion to discuss the hostage situation with Malian President Amadou Toumani Toure.

Late Tuesday, published a letter sent on September 1 by the prefect of Arlit, Seydou Oumanou, to Areva and other firms in the region, in which he warned that the security in the region was “deteriorating.” He reported that a column of eight Toyota vehicles had been spotted in the area. The cars were carrying armed men “whose aim, according to (our) information, consists of making off with military equipment and foreign personnel,” Mr. Oumanou claimed.

The prefect warned Areva that, as a result, “the threat by the group AQIM must be taken seriously.” In a press statement, Areva denied that the letter “communicated special information” and defended itself against suggestions that it had not taken sufficient security measures to protect its employees.

“Areva is a responsible enterprise,” the company said. “In these circumstances, the group regrets the inappropriate controversy regarding the cited threats.” AQIM has often threatened to attack French interests in the region, particularly after six of its members were killed earlier this year in a raid on one of its bases in Mali by French and Mauritanian soldiers.

That raid was undertaken to rescue a 78—year—old French aid worker, kidnapped in April by AQIM. He was subsequently executed.

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