"We are getting US troops to assist in training and technical support," Major General Samaila Uba, a spokesman for Nigeria's Defense Headquarters, told AFP.

The Wall Street Journal was the first to report the deployment, which will supplement a US small team already in the country to aid the Nigerians with air strike targeting.

The additional troops, expected to arrive in the coming weeks, will provide "training and technical guidance," including by helping their Nigerian counterparts coordinate operations that involve air strikes and ground troops simultaneously, the US daily said.

A US Africa Command spokeswoman confirmed the details of the report to AFP.

Nigeria has been under diplomatic pressure from the United States over insecurity in the country, which US President Donald Trump has characterized as "persecution" and "genocide" against Christians.

Although there are instances where Christians are specifically targeted, Muslims are also killed en masse, with Trump's senior advisor on Arab and African affairs Massad Boulos saying last year Boko Haram and Islamic State "are killing more Muslims than Christians."

Abuja rejects allegations of Christian persecution in Nigeria, a framing long used by the US religious right.

So do independent analysts, who point to a broader state failure to curb violence from jihadist groups and armed gangs across swaths of sparsely governed countryside.

Despite the diplomatic pressure, Nigeria and the United States have found common ground in increasing military collaboration.

The US targeted militants in northwest Sokoto state with strikes in December, in a joint operation with Nigeria, officials from both countries said.

Going forward, the US military has said it will supply intelligence for Nigerian air strikes and work to expedite arms purchases.

While the 200-troop deployment represents a scaling up of that collaboration, "US troops aren't going to be involved in direct combat or operations," Uba told the Journal.

Nigeria requested the additional assistance, he added.

Africa's most populous country is battling a long-running jihadist insurgency concentrated in its northeast, while non-ideological "bandit" gangs conduct kidnappings for ransom and loot villages in the northwest.

Across the center of the country, violence erupts among mostly Christian farmers and Muslim Fulani herders -- though researchers say the main cause is access to dwindling land and resources.