A contingent of French Special Forces troops was reported to have deployed in Niamey, Niger's capital. Their stated mission is to support Niger's military hunt the kidnappers and their captives but they could be the vanguard of a larger French force across the region.
French surveillance aircraft based in neighboring Mali, where AQIM also operates, have flown to Niamey to help in the search.
The abductions Thursday took place near the French-owned Arlit uranium mining facility in the north of the country and although no group has claimed responsibility the incident bore all the hallmarks of al-Qaida in the Islamic Maghreb or Tuareg insurgents who often work with the jihadists.
The kidnappings came six weeks after French President Nicolas Sarkozy declared war on AQIM for beheading a 78-year-old French hostage, Michel Germaneau, in Mali July 24, three months after he was kidnapped in Niger.
AQIM said it killed Germaneau in retaliation for an attack on a jihadist base in the desert two days earlier by French and Mauritanian troops. Six jihadists were killed in the raid, which was seen as a botched bid to rescue Germaneau.
The French government said that operation was intended to thwart an imminent, but unspecified, AQIM attack against a West African nation, presumably Mauritania which has taken a hard line against the jihadists.
The raid was the first counter-terrorism operation in northern Africa in which Western forces are known to have participated.
AQIM leader Abdelmalik Droukdel issued an audio tape in which he declared that Sarkozy had by initiating the July 22 raid "opened the gates of hell on himself, his people and his nation."
That suggested AQIM, while going after French targets in North Africa, might also seek to carry out attacks in France itself, escalating the confrontation with Sarkozy to a dangerous new level.
The Arlit kidnappings mark AQIM's first known operation in northern Niger, where the French state-owned company Areva has several uranium mines that provide 40 percent of France's requirements for nuclear power generation.
That indicates a menacing expansion of AQIM's operational zone in a region that is vital to France's economic well-being.
France has been plagued by Islamist terrorists from Algeria and other North African states since the 1990s, mainly members of the now-defunct Armed Islamic Group which fought against Algeria's military government for most of that decade.
France has never been singled out by al-Qaida's various networks, in part because it didn't join the U.S.-led invasion of Iraq in March 2003.
But the Armed Islamic Group, known by its French acronym GIA, was infamous for its brutality, beheading its victims and massacring civilians before it splintered. Its hard-liners eventually morphed into AQIM and swore allegiance to Osama bin Laden.
France is the first European state to become directly involved in fighting jihadists in North Africa, which was part of the empire France carved out in Africa starting in the 17th century.
European intelligence services have been battling North African jihadists for years, long before 9/11 finally thrust the Americans into combating terrorism.
The emergence of AQIM in September 2006 gave rise to concerns that the jihadists would unleash a wave of attacks in Western Europe, where the North African jihadists long maintained elaborate financial and logistics support networks.
That hasn't happened, although several major plots have been foiled. One of the most ambitious occurred in 1994 when four GIA activists seized an Air France Airbus in Algiers on Christmas Eve and threatened to crash it into the Eiffel Tower in Paris.
French police commandos stormed the aircraft in Marseille, where it was being refueled. They killed all the hijackers before they could carry out an operation that would have preceded 9/11 by seven years -- an example of what the Maghreb jihadists may be capable of, particularly if they still have some sort of support network in France.
Many Western European states, particularly France, Spain, Belgium and Italy, have large, often disaffected, Muslim communities made up largely of North Africans in which the jihadists would be able to operate.