The Pentagon is poised to send dozens of Special Operations advisers to the front lines of Nigeria’s fight against the West African militant group Boko Haram, according to military officials, the latest deployment in conflicts with the Islamic State and its allies.

Their deployment would push American troops hundreds of miles closer to the battle that Nigerian forces are waging against an insurgency that has killed thousands of civilians in the country’s northeast as well as in neighbouring Niger, Chad and Cameroon. By some measures, Boko Haram is the world’s deadliest terrorist group.

The deployment is a main recommendation of a recent confidential assessment by the top United States Special Operations commander for Africa, Brig. Gen. Donald C. Bolduc. If it is approved, as expected, by the Defense and State Departments, the Americans would serve only in noncombat advisory roles, military officials said.

Even as President Obama has drawn down the large American armies sent to Iraq and Afghanistan, he has relied heavily on Special Operations forces to train and advise local troops fighting the Islamic State, also known as ISIS or ISIL, and to carry out clandestine counterterrorism missions.

Already, about 50 American commandos are advising fighters battling the Islamic State in eastern Syria. Scores more in a new, secret kill-or-capture unit are hunting Islamic State militants in Iraq. The Pentagon has offered to send American advisers with Iraqi brigades on the battlefield instead of restricting them to bases inside Iraq. Dozens of American commandos are conducting surveillance missions in Libya and counterterrorism missions in Somalia.

“Rather than entangle U.S. combat forces on the ground, help build the capacity of regional forces to tackle their countries’ security challenges,” said Jennifer G. Cooke, Africa director at the Center for Strategic and International Studies in Washington, who visited Nigeria last month. “Training and advising and perhaps imparting the lessons we learned the hard way is a good thing.”

Since taking office last year, Nigeria’s president, Muhammadu Buhari, has vowed to pursue a military campaign against Boko Haram more vigorously than his predecessor, Goodluck Jonathan. His shake-up of the military high command and new cooperation with neighboring countries has proved effective.

Mr. Buhari, a former general, has boasted of the military’s successes in wresting control of a huge portion of terrain from the group, declaring a “technical” victory late last year. But while the military has killed or captured thousands of militants and put an end to raids of villages by dozens or more fighters, the group has still carried out suicide attacks at a relentless pace in Nigeria and neighboring countries.

“Despite losing territory in 2015, Boko Haram will probably remain a threat to Nigeria throughout 2016 and will continue its terror campaign within the country and in neighboring Cameroon, Niger and Chad,” James R. Clapper, the director of national intelligence, told the House Intelligence Committee in Washington on Thursday.

To help combat this threat, Mr. Buhari has embraced American assistance, ending several years of tense relations that sank to new lows in 2014 when the United States blocked the sale of American-made Cobra attack helicopters to Nigeria from Israel, amid concerns about Nigeria’s protection of civilians when conducting military operations.

Groups like Human Rights Watch say the Nigerian military has at times burned hundreds of homes and committed other abuses as it battled Boko Haram and its presumed supporters.

Nigeria’s ambassador to the United States responded sharply at the time, accusing Washington of hampering the country’s effort to defeat Boko Haram. American officials also expressed hesitancy about sharing intelligence with the Nigerian military, fearing their ranks had been infiltrated by Boko Haram, an accusation that further infuriated Nigerian leaders.

In December 2014, Nigeria canceled the last stage of American training of a new Nigerian Army battalion that was to take the lead in fighting terrorists.

Those days now seem over. This month Linda Thomas-Greenfield, the State Department’s top diplomat for Africa, announced that the suspended training for the Nigerian infantry battalion would resume soon. Nigeria will provide the ammunition.

Two weeks ago, Gen. David M. Rodriguez, the head of the Pentagon’s Africa Command, hosted Nigeria’s chief of defense staff, Gen. Abayomi Gabriel Olonisakin, at the American headquarters in Stuttgart, Germany. “To contain Boko Haram, working together is a priority,” General Rodriguez told his visitor.

About 250 American service members have deployed to a military base in Garoua, Cameroon, where United States surveillance drones flying over northeastern Nigeria are sending imagery to African troops. Drone photos recently helped the Nigerian Army avoid a major Boko Haram ambush, according to a senior American intelligence officer.

Another breakthrough occurred late last year when General Bolduc, a Green Beret with multiple Special Forces tours in Afghanistan, visited Nigeria. When officials there asked for assistance, General Bolduc quickly sent an assessment team to conduct a 30-day review.

Among the team’s main recommendations was to position “small dozens” of Special Forces in Maiduguri, a major city in the northeast on the edge of the conflict, to help Nigerian military planners carry out a more effective counterterrorism campaign. British special forces are already assisting in the city. (The American military now maintains only a tiny intelligence cell in Abuja, Nigeria’s capital.) Nigerian military officials have embraced the recommendations and are drawing up detailed requests, American officials said.

Just last fall, life seemed to be turning back to normal in the areas near Maiduguri, which for years had been the epicenter of Boko Haram’s activities. But after a major military operation uprooted the militants from nearby villages they had seized, many fighters have returned to Maiduguri to launch repeated suicide bombing operations in the city or in villages on the outskirts that have caused dozens of deaths.

At the end of last year, fighters attacked the city with rocket-propelled grenades and several suicide bombs. Residents say they eye one another with suspicion, especially women wearing religious gowns, fearful that explosives may be hidden underneath.

These relentless attacks have put more pressure on Nigeria and its neighbors to marshal their forces against a common enemy.

After taking office last year, Mr. Buhari began forging relationships with the presidents of neighbouring countries to establish information-sharing and to build trust between his nation and Niger, Cameroon and Chad. But grouping the four nations together to share information and untangling decades of mistrust among them have proved harder.

A regional task force established by the countries last year has largely stalled amid lingering distrust and differing views about the threat. Less than half of the task force’s $700 million budget has been raised, and sinking oil prices have hurt the economies of Chad and Nigeria, Ms. Cooke said in congressional testimony this week.

Still, working together has yielded victories.

Earlier this month, the Cameroonians teamed up with the Nigerian military as part of a joint operation on Nigerian soil just across the border in the far north, killing more than 160 Boko Haram fighters, dismantling a logistics hub for the fighters and destroying explosive devices, according to officials there. (New York Times)

•Photo shows U.S. President Barack Obama.