Nigerian President Muhammadu Buhari told BBC that the country's army is close to defeating Boko Haram. Getty Images/Sean Gallup

The Nigerian military is close to meeting its December deadline to defeat the Boko Haram militant group, President Muhammadu Buhari told BBC late Wednesday. The group, which has pledged allegiance to the Islamic State group, has waged a bloody insurgency for years and continues attacks in Nigeria and neighboring countries.

Buhari reportedly said that Boko Haram is no longer capable of carrying out conventional attacks against security forces or population centers. The militant group, which aims to establish an ISIS-style government in Nigeria, has killed tens of thousands of people and has forced more than 2 million people to flee their homes in the country over the last six years.

"I think, technically, we have won the war," Buhari told BBC, adding that Boko Haram has been forced to reduce its suicide bombings as a result of the military action. "Boko Haram has reverted to using improvised explosive devices (IEDs)," Buhari reportedly said. "They have now been reduced to that.

"Boko Haram is an organized fighting force, I assure you, [but] we have dealt with them."

However, critics of the government have argued that it has exaggerated the scale of its success against Boko Haram. Buhari's comments came the same day security and administrative sources said that suspected Boko Haram militants launched four attacks in 24 hours on villages in neighboring Niger, Chad and Cameroon, killing at least seven people, Reuters reported.

Last week, reports claimed that Boko Haram militants killed 30 people during attacks in three villages in northeastern Nigeria. Buhari said Wednesday that the militants had been driven out from Adamawa and Yobe states but remained a force only in Borno state.

"They cannot now marshal forces and attack towns or attack military installations and so on as they did before… I don't think this is mad talking,” Buhari reportedly said, adding that the Nigerian military has been reorganized and reequipped, and has received training from the British, the Americans and the French.

Last month, the Institute of Economics & Peace estimated that Boko Haram has killed more people in 2014 than ISIS, according to a report from the New York Times. Last year, the deaths attributed to Boko Haram alone increased by more than 300 percent, the report added.