* Two groups linked to Niger attacks formally join forces
* In statement, commander seeks to tap into Egypt violence
By Kissima Diagana and John Irish
NOUAKCHOTT/PARIS, Aug 22 (Reuters) - Two Islamist groups that broke away from al Qaeda's North African wing and fought in Mali have merged, pledging to attack French interests, according to a statement published on Thursday.
The move unites fighters led by Mokhtar Belmokhtar, the alleged mastermind of an attack on an Algerian gas plant in January, with MUJWA, an Islamist group that was scattered by a French offensive on al Qaeda-linked rebels in Mali this year.
The two groups had already jointly claimed responsibility for raids in May that killed dozens at a barracks and damaged a uranium mine operated by France's Areva in Niger.
"It is the birth of a group that includes Mujahideen and even Muslims in North Africa from the country of the Nile and the Atlantic," Mauritania's Nouakchott Information Agency, ANI, quoted Belmokhtar as saying in a statement it received.
It was not possible to independently verify the report but North African Islamist militants frequently use ANI to publish their statements.
The new name for the group was given as Al-Mourabitoun. It was not immediately clear who had been named its leader.
Belmokhtar is quoted as saying the group aimed to create an Islamic state and recent events in Egypt had shown how the "Zionist and Crusader" forces wanted to destroy Islam.
France sent warplanes and thousands of troops to Mali in January and officials say hundreds of Islamists were killed in bombing raids and battles in Mali's mountains and deserts.
Chad, which took part in some of the heaviest fighting alongside French troops, had claimed to have killed Belmokhtar. But no evidence was provided and diplomats in the region have long doubted the claim.
MUJWA and Belmokhtar's fighters appear to have escaped the brunt of the offensive, security officials say, a view backed up by their raid on neighbouring Niger.
In the statement sent to ANI, Belmokhtar said the group would concentrate on attacking French interests.
"We say to France and its allies in the region ... the Mujahideen have met and agreed to defeat your armies and destroy your plans and projects," he said.
Belmokhtar was charged by U.S. prosecutors in July with participating in the In Amenas gas plant attack that killed dozens of workers.
He formed his own group after years as a commander of Al Qaeda in the Islamic Maghreb (AQIM) in the Sahara, where he acquired a reputation as a smuggler as well as a jihadist.
MUJWA emerged in late 2011, it too claiming to have split from AQIM. However, the Islamists collaborated during their nine-month occupation of northern Mali last year. (Writing by Bate Felix; Editing by David Lewis and Andrew Roche)