The Chad Government has declared an immediate closure of its border with Nigeria on heightened security concerns fueled by rumors of purported U.S. forces’ movement in parts of West Africa.

Military sources in N’Djamena confirmed on Monday that President Mahamat Idriss Déby Itno ordered a military lockdown on the Nigerian border after intelligence indicated that terrorist actors from Northern Nigeria were planning to cross into Chad.

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

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

Security experts say Chad’s action is a precautionary step aimed at protecting its borders and preventing infiltration by militants who may seek to exploit the current instability in the region.