"We hope there will be a transition led by a civilian and in keeping with the constitutional order," the UN envoy for west Africa, Mohamed Ibn Chambas, told a news conference. "If not, the consequences are pretty clear. We want to avoid having to impose sanctions on Burkina Faso."
The military named a high-ranking officer, Isaac Zida, to lead the country's transition yesterday. A day earlier, Compaore was forced to resign as plans to extend his 27-year rule exploded into violent demonstrations that saw parliament set ablaze and hundreds of thousands take to the streets.
They "assured us that they had well understood the message," Chambas said.
The former French colony prepared for another day of mass protest as opposition and civil society leaders challenged moves by the military to step into the power vacuum left by Compaore's ouster.
The developments are being closely watched across a continent where several other veteran heads of state are also trying to cling to power.
Under the constitution, the speaker of parliament should serve as transitional leader.
Opposition and activist leaders swiftly issued a statement warning the military against a power grab, demanding instead a "democratic and civilian transition".
"The victory born from this popular uprising belongs to the people, and the task of managing the transition falls by right to the people. In no case can it be confiscated by the army," they said in a statement.
They called a new mass rally in the capital Ouagadougou today at the site now nicknamed "Revolution Square".
