In a video released on Friday, Abubakar Shekau said: "We have not made ceasefire with anyone. We did not negotiate with anyone. It's a lie.
"We will not negotiate. What is our business with negotiation? Allah said we should not."
Hopes were raised earlier this month when Nigeria's chief of defence staff, Alex Badeh, announced a truce with the group.
"They've assured us they have the girls and they will release them," he said. "I am cautiously optimistic."