US President Donald Trump threat on Sunday to deploy the US military to Nigeria or carry out air strikes to stop what he called the killing of large numbers of Christians in the West African country has already had a domino impact in West Africa.

Hours after the warning, Chad announced on Monday immediate closure of its border with Nigeria following intelligence reports suggesting that terrorist groups operating in northern Nigeria are attempting to flee into Chadian territory.

Trump made the comment on Sunday evening as he headed back to Washington after a weekend at his vacation home in Florida.

According a report by Reuters, Trump threatened on Saturday to take military action against Nigeria if Africa’s most populous country failed to crack down on the killing of Christians.

The port said US president’s threat of military action came a day after his administration added Nigeria back to a “Countries of Particular Concern” list of nations that the US says have violated religious freedoms. Other nations on the list include China, Myanmar, North Korea, Russia and Pakistan.

Asked if he envisioned troops on the ground or air strikes in Nigeria, Trump told reporters aboard Air Force One on Sunday: “Could be. I mean, other things. I envisage a lot of things. They’re killing record numbers of Christians in Nigeria… They’re killing the Christians and killing them in very large numbers. We’re not going to allow that to happen.”

According to sources in N’Djamena, the decision comes amid growing tension over an alleged US invasion plan in West Africa, which has prompted several countries in the region to tighten security and reinforce military positions.

According to Zagazola Makama, Chadian troops and armoured vehicles have been deployed to critical routes from Nigeria, and all units are now at full readiness. President Déby reportedly warned that “no armed group or foreign force will be allowed to enter Chadian soil under any disguise.”

The border closure comes amid growing regional tension and speculation over America’s alleged military activities in the Sahel and West Africa.

Chadian Armed Forces have been placed on maximum alert with troops, armoured vehicles and surveillance drones deployed along key border routes. President Mahamat Idriss Déby Itno was quoted as saying that “no armed group or foreign force will be allowed to enter Chadian soil under any disguise.”

Officials say the move is aimed at preventing cross-border infiltration and maintaining national security as uncertainty grows across the Sahel region.

• Tell Media / Agencies report