President Donald Trump said he has instructed the Pentagon to prepare for possible action in Nigeria, saying the U.S. could go in “guns-a-blazing” and halt aid if the government there “continues to allow the killing of Christians.”

“If the Nigerian Government continues to allow the killing of Christians, the U.S.A. will immediately stop all aid and assistance to Nigeria, and may very well go into that now disgraced country, “guns-a-blazing,” to completely wipe out the Islamic Terrorists who are committing these horrible atrocities,” the president said in a post on his social media platform. “I am hereby instructing our Department of War to prepare for possible action.”

He added, “WARNING: THE NIGERIAN GOVERNMENT BETTER MOVE FAST!”

On Friday, Trump said he was designating Nigeria as a “country of particular concern,” a legal designation from the U.S. State Department for countries “responsible for particularly severe violations of religious freedom,” with Trump saying that “Christianity is facing an existential threat in Nigeria.”

Trump said he asked Rep. Riley Moore, R-W.V. and Rep. Tom Cole, R-Okla., and the House Appropriations Committee, for a report on the matter. 

Nigeria’s population of more than 230 million is about evenly split between Muslims and Christians. Violence in the country has grown amid near daily attacks by armed groups and bandits in northern Nigeria, Amnesty International reported earlier this year, calling the mounting death toll a “humanitarian crisis.”

However, the patterns of violence are often complex. Christians have been targeted, as have other religious groups. People have also been targeted by violence based on their ethnic group and how they make their living. 

After Trump’s first post, Nigerian President Bola Ahmed Tinubu pushed back, writing “The characterisation of Nigeria as religiously intolerant does not reflect our national reality, nor does it take into consideration the consistent and sincere efforts of the government to safeguard freedom of religion and beliefs for all Nigerians.” 

Tinubu said his administration has taken steps to maintain “an open and active engagement with Christian and Muslim leaders alike and continues to address security challenges which affect citizens across faiths and regions.” And he said he was committed to working with the U.S. and the international community to “deepen understanding and cooperation on protection of communities of all faiths.”

Nigeria has seen a resurgence of the homegrown Islamic militant group Boko Haram this year, according to the Associated Press. 

An attack in northern Nigeria in September killed dozens, the AP reported. 

ABC News’ Victoria Beaule contributed to this report.