The Pentagon is considering sending military advisers to Nigeria to train local troops to fight Boko Haram insurgents and boost security in the violence-wracked nation, a US official said Friday.

The defense official, who spoke on condition of anonymity, said the US military made a string of recommendations after Nigeria's leaders asked for help determining "possible courses of action" in the fight against the Islamist militants.

One recommendation was to send a group of US advisers -- most likely special operations troops -- to Nigeria to train local forces. They would not be in a combat role.

Such a mission would be a resumption of an earlier Pentagon effort that Nigeria stopped in late 2014 amid US concerns of suspected Nigerian army abuses and its failure to protect civilians.

The two countries also had strained diplomatic ties stemming in part from the US blocking Nigerian efforts to buy Cobra attack helicopters.

The official said ties have improved under the new Nigerian president, Muhammadu Buhari, who has vowed to do more than his predecessor Goodluck Jonathan to fight Boko Haram.

The New York Times first reported the potential deployment Friday, saying the Pentagon was poised to send "dozens" of special operations advisers to Maiduguri, capital of northeast Borno state.

But the defense official downplayed the speed of any deployment, and said the operation was still being discussed.

"I don't think anyone is ready to approve anything today," the official said. "Recommendations were made, these are still being assessed."

- 'Terrorist dog whistle' -

The Pentagon later said in a statement that there were "still a number of decision points yet to be resolved with regard to the full assessment across the US government."

The US military already has about 40 personnel in Nigeria performing a variety of functions including embassy support and military training.

"These same type of advise-and-assist operations are ongoing across the African continent," the statement read.

"US military advisors are working every day to assist African partner nations in providing for their own defense and enable regional solutions to collective problem sets."

Yan St-Pierre, an expert with the Modern Security Consulting Group (MOSECON) in Berlin, said the presence of US and other troops in Maiduguri could trigger a limited number of attacks in the area, adding to the already very high security risk.

"It could indeed encourage more attacks on Maiduguri and its vicinity, but the presence is too minimal to become a 'dog whistle' for terrorists," he said.

"Where it could become interesting is how the Nigerian population will react to this. Some see it as the Nigerian army to admitting it is not able to do the job, others see it as another form of foreign intervention."

The US embassy in Nigeria said in 2014 that it regretted the end of the training program, which was offered following Boko Haram's abduction of 276 schoolgirls in northeastern Nigeria.

A number of foreign powers sent surveillance and intelligence specialists to Nigeria to help the military search for the 219 teenagers still held.

US advisers and special operations troops are playing a growing role in the global fight against Islamist extremists, including in Iraq, Syria and Libya.

The US military is also active in Niger, where it uses drones to watch over the broad strip of Sahel territory on the southern side of the Sahara. The pilotless aircraft also monitor Boko Haram.