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 20 people and wounding dozens more in attacks that showed militant violence spreading across West Africa.
The coordinated dawn assault 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 parts of the Sahara far from their bases.
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, Defence Minister Mahamadou Karidjo told state radio. Three Islamists were also killed.
After a fierce gunbattle, security forces restored calm but one Islamist was holding at least three military cadets hostage in a house, military sources and officials said.
"The situation is under control and the search for other attackers is under way," Karidjo told state radio.
Further north in Arlit, at least 14 civilians were injured and two Islamists killed in a car bomb attack at Areva's Somair mine, the largest in the country, the minister said. Areva later said one of its injured staff had died.
Niger officials said crushing and grinding units had been badly damaged at the Somair mine, which is an important part of France's energy supply chain. [ID:nL6N0E42NPA] Niger provides around 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 which 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.
President Mahamadou Issoufou, who has emerged as a strong ally of France and the United States against Islamists in the region, canceled a trip to an African Union summit in Ethiopia. He has decree 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 West African force in Mali, sending 650 troops. Islamist suicide bombers have carried out a spate of attacks there in recent months, including one on Niger's barracks in Menaka.
In January, a regional al Qaeda commander claimed responsibility for a mass hostage-taking at the giant In Amenas gas plant in Algeria, in response to the French offensive in Mali. At least 37 foreigners were killed in the attack.
Niger itself is no stranger to Islamist raids. Seven workers, including five French nationals, were kidnapped in 2010 by AQIM in remote Arlit, which lies 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, who had imposed violent sharia law in northern Mali, across borders into neighboring Sahel states, stirring fears of a radicalization of Islam in 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 which they used in their attack.
In Agadez, a suicide bomber drove a Toyota truck through the barrier of the military base at around 5.30 a.m. and detonated his explosives when soldiers opened fire, military sources said.
Soldiers returned the dusty town to calm after gunbattles with Islamists. "One attacker has taken two or three soldiers hostage and is holed up in a house. We have him surrounded," said one source.
Areva, meanwhile, strongly condemned the attack on its staff. "We express our solidarity with the government and the people of Niger in this common trial," it said in a statement.
The firm said security at the site was being handled by the Niger military. French sources said in January Paris planned to send special forces for extra protection.
Aside from Islamist threats in its north, Niger also faces militants along its southern border with Nigeria. Its armed forces recently took part in a bloody joint operation against Boko Haram Islamists in the Nigerian frontier town of Baga.
Nigeria again asked its northern neighbor for military aid this week after President Goodluck Jonathan launched a major offensive against Boko Haram insurgents.
(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)