A top African Union official Friday denounced the military coup in Niger and called for a quick return of "constitutional order," saying the organization was ready to help facilitate the process. Jean Ping, the chairman of the 53-nation body, said he was following developments in the nation with "concern" after a Niger military official announced that the constitution has been suspended. In addition to the suspension, President Mamadou Tandja is said to be detained in a military camp. "The chairperson of the commission stresses that the relevant AU instruments systematically condemn any unconstitutional change and, accordingly, he condemns the seizure of power by force that took place in Niger," said a statement from Ping's office. The violence may have been prompted by a collapse of talks between the governmentand the opposition over a recent referendum allowing the president to hold power indefinitely, according to the United Nations, which called for a quick resolution. "The secretary-general has called on the stakeholders in Niger to swiftly revert to constitutional order in the settlement of the political crisis," said a statement from UN Secretary-General Ban Ki-moon. Thursday's order to suspend the constitution was attributed to the Superior Council for the Restoration of Democracy. It also suspended all institutions, urged citizens to remain calm and called for support from the international community. Dana Palade, a spokeswoman for World Vision, who is in the capital, Niamey, said gunfire rang out in the streets Thursday. The French Embassy also reported hearing intermittent gunfire near the palace.