United Nations (UN) Secretary-General Antonio Guterres said Russian troops on the Ukraine border are "not peacekeepers" and called for an immediate ceasefire.

"When troops of one country enter the territory of another country without its consent, they are not impartial peacekeepers. They are not peacekeepers at all," Guterres told reporters at the UN.

"We need restraint and reason. We need de-escalation now," he said. "I urge all to refrain from actions and statements that would take this dangerous situation over the brink."