A military coup in Guinea-Bissau has drawn sharp criticism from an African election observer mission and left dozens of leaders, including former Nigerian President Goodluck Jonathan, stranded after soldiers seized power, suspended the electoral process, and shut down airports. The coup unfolded on Wednesday after both incumbent President Umaro Embaló and his main challenger, Fernando Dias, separately claimed victory in Sunday’s presidential election, despite the electoral commission not releasing official results. Soldiers subsequently took control of state institutions, closed all borders, and shut down airports.

In a joint statement, the observer mission, which includes the African Union, ECOWAS, and the West African Elders Forum, said it was “deeply concerned” about the military intervention, calling it “regrettable” that the takeover came shortly after meeting the two top candidates, who had assured them they would respect the will of the voters. The mission urged the AU and ECOWAS to take urgent steps to restore constitutional order and demanded the immediate release of all detained officials.

The delegation, part of a 36-member joint election observation mission deployed to monitor the election, is scheduled to depart Guinea-Bissau on November 29, though it is unclear whether the airport shutdown will affect their exit. Former Nigerian President Goodluck Jonathan is among those stranded in the country as a result of the military’s actions.