A plane carrying four African presidents headed for the Mali capital of Bamoko for crisis talks has turned around without landing, the Associated Press reports.

View Photo Gallery: People rally to protest the recent military coup and call for a return to constitutional order, in Bamako, Mali on Thursday.

Presidents from Ivory Coast, Benin, Niger and Burkina Faso had planned to meet with the army captain who initiated a coup in Mali last week. West Africa’s regional bloc, ECOWAS, is threatening to use military force if Capt. Amadou Haya Sanogo doesn’t cede power.

The reason for the aborted mission to Mali’s capital was not immediately given, but Reuters reporter David Lewis said pro-coup protesters at at the airport were to blame:

#ECOWAS visit to #Mali off after pro coup protestots invade #Bamako airport. Clashes between rival camps also in town.

— David Lewis (@DG_Lewis) March 29, 2012

Burkina Faso’s president Blaise Compaore has also just arrived in Abidjan, Ivory Coast, where he will discuss why the plane turned around, according to Ivory Coast-based journalist Jean Jacques.

Despite the military junta’s effectiveness at blocking ECOWAS on Thursday, the group is unlikely to hold onto power for long, Boston University international relations professor Michael Woldemariam, whose studies focus on international security and African politics, told BlogPost in an e-mail.

“Mali coups plotters will find themselves squeezed, if they haven’t already,” Woldemariam wrote. “What is key for international stakeholders is to provide the junta’s leaders a credible option for exit -- in other words, a guarantee that they will not be punished if they relinquish power.”

Rebel soldiers took over the presidential palace last Thursday, and the constitution was suspended. The president, Amadou Toure, told Radio France Internationale that he is in the capital and is not a prisoner.

On the day of the coup, Sanogo appeared on national television to announce a nationwide curfew and urge people to remain calm:

Despite the rebel leader’s urging, Malians have filled the streets to protest the coup and call for a return to constitutional order.

This story has been updated.