U.S. President Donald Trump speaks in the Oval Office of the White House in Washington, D.C., U.S., February 11, 2025. REUTERS/Kevin Lamarque

WASHINGTON (Reuters) -U.S. President Donald Trump said on Friday that Christianity faces a threat in Nigeria and he was adding the West African nation to a State Department watch list.

"Christianity is facing an existential threat in Nigeria. Thousands of Christians are being killed. Radical Islamists are responsible for this mass slaughter," Trump wrote in a post on Truth Social.

He said he was putting Nigeria, Africa's top oil producer and most populous country, on a "Countries of Particular Concern" list of nations the U.S. finds have engaged in religious freedom violations. The list includes China, Myanmar, North Korea, Russia and Pakistan among others, according to the State Department website.

Trump said he was asking U.S. Representatives Riley Moore and Tom Cole, as well as the House of Representatives Appropriations Committee, to look into the matter and report back to him.

(Reporting by Doina Chiacu; Editing by Susan Heavey and Andrea Ricci)