The Ivorian authorities have insisted the detained soldiers had arrived to join MINUSMA, the UN peacekeeping force in Mali.

But Farhan Haq, a spokesman for the UN Secretary General, said Tuesday."These are not UN peacekeeping troops, so they're not part of MINUSMA formally."

Haq added that they were part of the national support elements deployed by the contributing countries to back up their contingents. "That's a common practice in peacekeeping missions," he said.

Mali on Monday had said the troops from the Ivory Coast were armed and "mercenaries", having detained them on arrival.

None of the Ivorian soldiers detained were carrying weapons of war, said a statement from the Ivorian president's office after an emergency meeting of the National Security Council.

Mali's government has said its foreign ministry was not informed via official channels, denouncing a "flagrant violation" of the penal code relating to territorial integrity.

The incident takes place against a backdrop of tensions in Mali, one of the poorest and most unstable countries in Africa.