Buhari also thanked the United States for helping Nigeria fight the Boko Haram insurgency.
The President said this on Monday, April 30, 2018, in Washington DC during the bilateral talk with U.S. President Donald Trump.
He again blamed the ongoing killing in Nigeria on the late Libyan dictator Muammar Gaddafi fighters, who he said fled to West African countries after Gaddafi's death.
Buhari said, "The problem of herders in Nigeria is a very long historical thing. The Nigerian herders don’t carry anything more than a stick and occasionally a machete to cut down foliage and give it to their animals, these ones are carrying AK-47.
"So, people should not underrate what happened in Libya. 43 years of Gaddafi, people were recruited from Sahel and trained to shoot and kill. With the demise of Gaddafi they moved to other countries and region and carried the experience with them."
The President also thanked the United States for its support in the fight against Boko Haram insurgency and its efforts in trying to get rid of terrorism across the world.
"We are grateful to the United States for agreeing to give us the aircraft that we asked for. We are even more grateful for the physical presence of the United States military officials in Nigeria. Our institutions in Nigeria, for training them and going to the Northeast to see how they are performing", Buhari said.
"The commitment of the United States to get rid of terrorism across the world, we have fast earned experience from that and we are grateful for it."
President Buhari was said to have arrived the White House at around 12 noon on Monday. He was accompanied by Nigeria's Ambassador to the U.S. Sylvanus Nsofor, Ministers of Foreign Affairs, Justice, and Trade and Investment, and Governors of Plateau and Ogun.
Others on the delegation were Chief of Defence Staff, Maj.-Gen. Gabriel Olonisakin, Senate Committee Chair on Foreign Affairs, Monsurat Sunmonu and her House of Representatives counterpart, Nnenna Ukejie.