WASHINGTON -- The bloody resolution of the hostage crisis in Algeria has brought into focus the broader challenges the United States and its allies face in confronting terrorist cells that have taken up sanctuary across northern Africa.
The United States and France have been courting Algeria for months, hoping to secure its support for an international effort to evict Islamic militants out of northern Mali.
But the militants' advance south, which set off an appeal for the French military intervention by the Mali government, and the hostage-taking at a gas-producing complex in the Sahara to the north have caught the United States by surprise and prompted fresh White House vows to combat terrorism in the region.
In taking on the militants, Western nations are confronting multinational bands that are often able to move with relative freedom across porous African borders. And those cells have many inviting targets to choose from: the region is rich with oil, gas, uranium and other international ventures that clearly represent Western interests and in some cases are poorly defended.
Also, with the United States and Britain determined not to send troops to Mali, and the French hoping to avoid an open-ended deployment there, Western nations must rely heavily on the forces of local nations who are not always open to outside advice.
Rudolph Atallah, a former Pentagon counterterrorism official, noted that one major terrorist group in the region, Al Qaeda in the Islamic Maghreb, had slowly branched out across borders. "To dismantle their network, the United States and its allies, African and European, will need a well-thought-out regional strategy," he said.
Forging that strategy will be far from easy, given those involved. The Algerians have an able, if heavy handed, military, but have not been eager to cooperate extensively with the United States or their neighbors. Libya's new government appears willing to cooperate but has little ability. Mali has little military ability and any enduring solution needs to be crafted with an eye to internal politics.
The harsh political realities of operating in Africa were evident during the hostage crisis in Algeria. Calculating that Algeria's cooperation will be needed for the campaign against the militants in Mali, both France and the United States were careful not to complain that the Algerians had mounted their hostage rescue operation without consultation, nor did they complain about the tactics.
"Algeria has an approach which to me, as I see it, is the most appropriate because there could be no negotiation," President François Hollande of France said Saturday.
Both France and the United States want Algeria to seal its borders with Mali, and France wants Algeria to continue to allow French planes to overfly its territory.
As the independent inquiry into the attack on the American mission in Benghazi observed, the Qaeda affiliate in North Africa and other militant factions in the region increasingly represent the new face of terrorism -- groups that are violently anti-American but not under the command and control of Qaeda leaders in Pakistan.
Al Qaeda in the Islamic Maghreb started out as an Algerian group that was fighting the Algerian government. Pushed out of Algeria, it found a sanctuary in northern Mali as did militants who left Libya following the fall of Col. Muammar el-Qaddafi.
The initial French and American strategy was to keep a low profile in the region, while training African troops who would be sent to Mali to contend with the Qaeda-affiliated militants.
There were growing signs that North Africa was becoming more dangerous. A Western security expert who was asked to assess the threat to Algeria's oil complex last year had reported an "elevated" risk due to the militants in Mali.
Still, the American and French plan assumed that the threat posed by the militants in Mali would be slow to build and that the West had time to organize an African military response -- the plan had been to deploy it in September this year.
But the militants' offensive in Mali and the attack in Algeria has demonstrated that the groups have a broader reach than anticipated and are prepared to take the offensive. The French intervention that followed has introduced a new variable in the equation.
"The ground has completely shifted," said Bruce Hoffman, an expert on terrorism at Georgetown University.
The Obama administration, which has sent 100 trainers to an array of African nations to help prepare African troops for their mission alongside the French in Mali, appears to be weighing how energetically to support the French military effort.
With the Americans still scrambling to determine just what happened in Algeria and to identify their dead, the United States has yet to detail how it plans to adapt its Africa strategy.
Experts say that any regional strategy needs to help African nations better secure their borders, both to limit the movement of militant factions and to reduce drug smuggling, which is one of their main forms of raising revenue.
Targeting the militant leaders who are responsible for most of the attacks is essential, Mr. Atallah said.
But he stressed that an enduring solution in Mali requires a political accommodation between the Mali government and the Tuaregs, a nomadic people in northern Mali, and ensure that Mali's armed force does not use the counterterrorism campaign as an excuse to repress them.
The problem of human rights abuses remains a nagging concern for any Western-supported military intervention. Human Rights Watch recently reported that the militant groups in northern Mali have recruited several hundred children to use as soldiers, and added that some children were at checkpoints that had been bombed by French aircraft.
With the White House largely focused on domestic issues and officials long wary about expanding the American military footprint in the region, some of the barrier to action may be self-imposed.
Mr. Hoffman said that the United States should consider stepping up its support for the French intervention by providing additional logistical support and perhaps making use of drones so that the French military can better carry out its operations and hand over the mission as soon as possible to African troops.
"I do not think the U.S. involvement has to be extensive," he said. "I do think we need to be more proactive."
Steven Erlanger contributed reporting from Paris.
This article originally appeared in The New York Times.