By Abdoulaye Massalatchi
NIAMEY (Reuters) - Islamist suicide bombers struck an army barracks and a French-run uranium mine in Niger on Thursday, officials said, killing 21 people and wounding dozens more in attacks that showed militant violence spreading in West Africa.
The coordinated dawn assaults on Areva's mine at Arlit and the military base in Agadez were claimed by the MUJWA militant group in retaliation for a French-led offensive this year against Islamist insurgents in neighboring Mali.
The attacks suggested Malian groups, despite the French campaign, remained capable of complex strikes against high-profile targets in remote parts of the vast Sahara.
In Agadez, the largest town in Niger's desert north, at least 20 soldiers were killed and 16 injured when suicide bombers attacked the barracks, Defense Minister Mahamadou Karidjo told state radio. Three Islamists were also killed.
After a fierce gunbattle, security forces restored calm.
"The situation is under control," Karidjo told state radio. "The armed forces reaffirm their commitment to defend Niger and its people, whatever the price."
One Islamist fighter, who held out inside a barracks in Agadez and was believed to be holding several military cadets hostage, was finally "neutralized" by Nigerien anti-terrorism units late on Thursday, a senior military official told Reuters.
"I don't know if he was taken alive, but apparently he didn't have any hostages. He was just making us think that to trick us," the official said.
Farther north in Arlit, at least 14 civilians were wounded and two Islamists killed in a car bomb attack at Areva's Somair mine, the largest in the country, the minister said. Areva said later one of its wounded staff died after the assault.
Niger officials said the grinding unit had been badly damaged at the Somair mine, which is an important part of France's energy supply chain. Niger provides about one-fifth of the uranium for France's nuclear reactors.
MUJWA and al Qaeda's North African wing AQIM had pledged to strike at French interests across the region after Paris launched a ground and air campaign in January that broke their 10-month grip over the northern two-thirds of Mali.
President Francois Hollande said France would do everything in its power to defend its interests in Niger.
"We will let nothing pass and will support Niger's authorities to end the hostage-taking and to annihilate the group that carried out these attacks," he told reporters.
FRENCH INTERESTS AT RISK
Niger's president, Mahamadou Issoufou, who has emerged as a strong ally of France and the United States against Islamists in the region, cancelled a trip to an African Union summit in Ethiopia. He has declared a 72-hour period of mourning.
The United States has stationed drone surveillance aircraft in Niger and deployed military personnel there to train West African forces before their deployment in Mali.
Niger has played a leading role in the African regional mission in Mali, sending 650 troops. Its barracks in the Malian town of Menaka was unsuccessfully targeted this month by a suicide bomber, part of a wave of recent attacks.
France's intervention in Mali has sparked threats to its interests in Africa. Last month, its embassy in Tripoli was car-bombed and a French family was kidnapped in Cameroon in February by Islamist sect Boko Haram, which cited the war in Mali. The seven hostages were released last month.
At least 37 foreigners were also killed during a mass hostage-taking by al Qaeda militants in January at the giant In Amenas gas plant in Algeria in response to the French offensive.
"The most recent attack will probably prompt France to bolster the security of its industrial assets and civilians in the Sahel region, bringing with it financial concerns," global risk consultancy Stratfor wrote in a report on Thursday.
Niger itself is no stranger to Islamist raids. Seven workers, including five French nationals, were kidnapped in 2010 by AQIM in remote Arlit, which is 1,200 km (750 miles) north of the capital, Niamey. AQIM still holds four of the Frenchmen.
But Thursday's bold attacks were the first in Niger since the French-led offensive drove Islamist insurgents across borders into neighboring Sahel states, stirring fears of a radicalization of the traditionally moderate region.
The official ANP state news agency, citing unnamed sources, said the militants had entered Niger via lawless southern Libya, carrying explosive belts that they used in their attack.
(Additional reporting by David Lewis in Bamako and James Regan, John Irish and Marion Douet in Paris; Writing by Daniel Flynn; Editing by Andrew Roche and Peter Cooney)