Prime Minister Albert Pahimi Padacket said on Thursday that the border closure was part of wider efforts by Chad to boost its military presence in the region.
“Faced with the perils that threaten all of the nation's territory, the government decided for one thing to close our land border with Libya, and for another to declare the regions bordering Libya military operation zones," Padacket said in a message broadcast on radio and television.
The premier added that following the military’s crackdown on those engaged in contraband border dealings, “Some isolated terrorist groups have gathered in the south of Libya, putting the northern frontier of our country potentially exposed to a serious threat of a terrorist infiltration.”
Padacket did not elaborate on the identity of those terror groups, but he possibly referred to the ethnic Tubu people, who used to live in the sparsely populated Tibesti desert border regions.
He also did not provide information on what "defeat" those militants suffered in Libya.
Chad has been a major ally of Western governments, especially France and the United States, helping them in their military intervention in the North Africa region over the past years. The country has a vast border with Libya, which plunged into chaos after the fall of former dictator Muammar Gaddafi in 2011.
Chad has also been part of a regional alliance led by Nigeria against the Boko Haram militant group. The Takfiri group, which is mainly based in northern Nigeria, has managed to expand its militancy to neighboring Chad, Niger and Cameroon.