The breakaway Al-Qaeda group "Signatories in Blood", which Belmokhtar founded in late 2012, said the bombings were in retaliation for Niger's support for military operations against Islamist extremists in neighbouring Mali, and threatened more attacks.
Chad claimed that Belmokhtar was killed during fierce fighting in northern Mali in early March, although France, which has led the armed intervention there, never confirmed his death.
In January, Belmokhtar's group seized the In Amenas gas plant in southern Algeria, also in retaliation for the French-led offensive in Mali.
During the four-day siege and army rescue operation that followed, 38 hostages, all but one of whom were foreign, and 29 militants were killed.
Branded a terrorist by some, Belmokhtar is seen by others as a common criminal.
He was born in 1972 in the Algerian desert city of Ghardaia.
In a rare 2007 interview, he said he was drawn away from home by his fascination with the exploits of the mujahedeen combating the Soviet invaders of Afghanistan, whom he joined in 1991 when he was barely 19.
It was in Afghanistan that he claims to have lost his eye when it was hit by shrapnel, and where he had his first contacts with Al-Qaeda.
Now nicknamed Lawar (The One-Eyed), he returned to Algeria in 1993, a year after the government sparked civil war by cancelling an election the Islamic Salvation Front was poised to win.
He joined the Armed Islamic Group (GIA), which conducted a violent campaign of civilian massacres in its battle against the government, sometimes wiping out entire villages.
Belmokhtar thrived thanks to his intimate knowledge of the nearly lawless "Grey Zone" of southern Algeria, northern Mali and neighbouring Niger. That success was strengthened by a network of tribal alliances that he cemented through marriage.
In 1998, the Salafist Group for Preaching and Combat (GSPC) broke away from the GIA. Belmokhtar, now also nicknamed "The Uncatchable" by a former French intelligence chief, went with them.
Nine years later, the GSPC formally adopted the jihadist ideology of Osama bin Laden and renamed itself Al-Qaeda in the Islamic Maghreb (AQIM).
These Islamists have spun a tight network across tribal and business lines that stretch across Africa's Sahel region, supporting poor communities and protecting all kinds of traffickers.
They are comfortable operating in harsh desert terrain and have made millions of dollars from the ransoms of European hostages.
Belmokhtar was pushed out as one of AQIM's top two leaders in northern Mali in October for what one regional security official said were his "continued divisive activities despite several warnings."
The precise details are not entirely clear, but his third nickname, "Mr Marlboro," could provide a hint.
With a reputation as a smuggling baron -- dealing in contraband cigarettes, stolen cars and even drugs, as well as profiting from illegal immigration networks -- Belmokhtar's commitment to AQIM's puritanical brand of Islam was questioned by some members of the group.
A Malian official said AQIM supremo Abdelmalek Droukdel had said Belmokhtar had been "dismissed for straying from the right path."
After his ouster from AQIM, Belmokhtar founded Signatories in Blood, which launched the Algerian gas plant attack days after France sent fighter jets, attack helicopters and troops into Mali on January 11.
Thursday's bombings in northern Niger targeted an army base in the main northern city of Agadez and a uranium mine majority-owned by French nuclear group Areva.
The jihadist group said it would continue attacking Niger until the country withdrew its forces from Mali, and also threatened France and other countries involved in what it called the "Crusader campaign" there.
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Chad claimed that Belmokhtar was killed during fierce fighting in northern Mali in early March, although France, which has led the armed intervention there, never confirmed his death.
In January, Belmokhtar's group seized the In Amenas gas plant in southern Algeria, also in retaliation for the French-led offensive in Mali.
During the four-day siege and army rescue operation that followed, 38 hostages, all but one of whom were foreign, and 29 militants were killed.
Branded a terrorist by some, Belmokhtar is seen by others as a common criminal.
He was born in 1972 in the Algerian desert city of Ghardaia.
In a rare 2007 interview, he said he was drawn away from home by his fascination with the exploits of the mujahedeen combating the Soviet invaders of Afghanistan, whom he joined in 1991 when he was barely 19.
It was in Afghanistan that he claims to have lost his eye when it was hit by shrapnel, and where he had his first contacts with Al-Qaeda.
Now nicknamed Lawar (The One-Eyed), he returned to Algeria in 1993, a year after the government sparked civil war by cancelling an election the Islamic Salvation Front was poised to win.
He joined the Armed Islamic Group (GIA), which conducted a violent campaign of civilian massacres in its battle against the government, sometimes wiping out entire villages.
Belmokhtar thrived thanks to his intimate knowledge of the nearly lawless "Grey Zone" of southern Algeria, northern Mali and neighbouring Niger. That success was strengthened by a network of tribal alliances that he cemented through marriage.
In 1998, the Salafist Group for Preaching and Combat (GSPC) broke away from the GIA. Belmokhtar, now also nicknamed "The Uncatchable" by a former French intelligence chief, went with them.
Nine years later, the GSPC formally adopted the jihadist ideology of Osama bin Laden and renamed itself Al-Qaeda in the Islamic Maghreb (AQIM).
These Islamists have spun a tight network across tribal and business lines that stretch across Africa's Sahel region, supporting poor communities and protecting all kinds of traffickers.
They are comfortable operating in harsh desert terrain and have made millions of dollars from the ransoms of European hostages.
Belmokhtar was pushed out as one of AQIM's top two leaders in northern Mali in October for what one regional security official said were his "continued divisive activities despite several warnings."
The precise details are not entirely clear, but his third nickname, "Mr Marlboro," could provide a hint.
With a reputation as a smuggling baron -- dealing in contraband cigarettes, stolen cars and even drugs, as well as profiting from illegal immigration networks -- Belmokhtar's commitment to AQIM's puritanical brand of Islam was questioned by some members of the group.
A Malian official said AQIM supremo Abdelmalek Droukdel had said Belmokhtar had been "dismissed for straying from the right path."
After his ouster from AQIM, Belmokhtar founded Signatories in Blood, which launched the Algerian gas plant attack days after France sent fighter jets, attack helicopters and troops into Mali on January 11.
Thursday's bombings in northern Niger targeted an army base in the main northern city of Agadez and a uranium mine majority-owned by French nuclear group Areva.
The jihadist group said it would continue attacking Niger until the country withdrew its forces from Mali, and also threatened France and other countries involved in what it called the "Crusader campaign" there.
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