The U.S. Embassy in the Burkinabe capital of Ouagadougou said in a notice to Americans that it had information the unnamed group is looking to abduct "unidentified U.S. citizen" near the northern city of Ouahigouya and had barred all official travel to the area without approval.
"U.S. citizens are strongly urged to exercise caution and avoid unnecessary travel to this region," the notice said.
The embassy said the group is affiliated with al-Qaida in the Land of the Islamic Maghreb, a group based in neighboring Mali that U.S. counterterrorism officials believe is growing more active and attracting recruits, threatening to further destabilize the already vulnerable Sahara region.
AQIM is still small and largely isolated, numbering a few hundred militants based mostly in the vast desert of northern Mali. But signs of stepped-up activity and the group's advancing potential for growth worry analysts familiar with the region.
It has yet to show a capability to launch foreign attacks, but it is widening its involvement in kidnapping and the narcotics trade, reaping profits that could be used to expand terror operations, officials and analysts said earlier this year.
The militants often partner with local criminals, who kidnap tourists and sell them to AQIM, which then demands ransoms, officials said. Those alliances cement contacts between the criminal groups and AQIM, broadening its reach and membership.
The kidnappings have had mixed results. Earlier this year, the group released French hostage Pierre Camatte after holding him for three months. The move was spurred by a Mali court decision that released four jailed AQIM members.
Some hostages have been killed — one, Edwin Dyer, was a British tourist who was captured with three others including two U.N. envoys. Britain had refused to pay ransom to the group.
Thursday's embassy warning was the latest in a series of threat notices sent to Americans in Burkina Faso and Mali beginning in early last month. Since June 5, the embassies in Ouagadougou and Bamako, Mali, have issued at least three others.
Associated Press writer Lolita C. Baldor contributed to this report.