Renegade soldiers said they seized power in Mali on Thursday, March 22 and ordered its borders closed, threatening to reignite instability in a Saharan region shaken by the conflict in Libya, Reuters reported.

The overnight coup bid was led by low-ranking soldiers angry at the government's failure to stamp out a two-month-old separatist rebellion in the north of the west African state.

Heavy weapons fire rang out throughout the night as the presidential palace came under attack. The whereabouts of President Amadou Toumani Toure, who oversaw a decade of relative stability, are unknown.

Mali's neighbors, the United Nations and world powers from Paris to Washington called for a return to constitutional rule.

The 7,000-strong army has for weeks sought better weapons to fight northern Tuareg rebels bolstered by heavily armed ethnic allies who fled Libya after fighting for ousted leader Muammar Gaddafi.

Members of the newly formed National Committee for the Return of Democracy and the Restoration of the State (CNRDR) read a statement on state television saying they had taken over.

"The CNRDR ... has decided to assume its responsibilities by putting an end to the incompetent regime of Amadou Toumani Toure," said Lieutenant Amadou Konare, spokesman for the CNRDR.

"We promise to hand power back to a democratically elected president as soon as the country is reunified and its integrity is no longer threatened," said Konare, flanked by about two dozen soldiers, in a statement marred by sound problems.