Tuareg separatist rebels battled the army for a key town in northern Mali on Thursday as a bid by west African leaders to negotiate a return to democratic rule with the junta fell apart before it began. The Tuareg fighters attacked the key town of Kidal as a crisis deepened 1,000 kilometres (620 miles) to the south in Bamako where supporters and critics of the junta clashed during rival rallies. Renegade soldiers angry at the government\'s inability to contain the two-month-old Tuareg rebellion, which has overwhelmed a poorly-equipped military, seized power a week ago, prompting stiff rebukes from Mali\'s foreign allies. A crack team of presidents from Ivory Coast, Burkina Faso, Liberia, Benin and Niger were on their way to Bamako to meet the putschists and wrest a deal on a return to constitutional order when they turned around mid-air. The U-turn was prompted by a pro-coup demonstration which saw dozens of people swarm the runway at Bamako\'s airport. \"The summit is postponed because of the security problem at the Bamako airport\" said Burkinabe Foreign Minister Djibrill Bassole. The regional heavyweights led by Ivorian President Alassane Ouattara, who also chairs the Economic Community of West African States (ECOWAS), returned to Abidjan for an emergency meeting Thursday afternoon after the incident. The 15-nation ECOWAS suspended Mali during a meeting on Tuesday and has warned its regional troops are on standby. In Bamako an anti-junta rally was interrupted by pro-coup demonstrators. \"There were clashes between the two camps at the labour exchange,\" a Malian security source told AFP, adding that security forces had intervened. President Amadou Toumani Toure was chased out of power just five weeks before April 29 elections were to end his tenure by soldiers angry at his \"incompetent\" handling of the Tuareg rebellion. The Malian military has been overwhelmed by the desert warriors, many of whom have recently returned, heavily-equipped and battle-hardened, from Libya where they fought alongside slain leader Moamer Kadhafi. They have seized several northern towns in fighting that has caused more than 200,000 to flee their homes. Amid a power vacuum in the south, the rebels have pushed their fight for independence and heavy fighting was under way in Kidal Thursday. \"We are under attack from the rebels ... we are fighting back,\" said a Malian soldier in the town, speaking on condition of anonymity. He said the Azawad National Liberation Movement (MNLA) was attacking from the north while fighters from an allied Islamist group, Ansar Dine (Defenders of Faith), were leading an offensive from the south. The MNLA in mid-January relaunched a decades-old fight for the independence of what the Tuareg consider their homeland. They were joined by renowned rebel Iyad Ag Ghaly who led the country\'s second Tuareg rebellion since independence between 1990 and 1995 and has returned as the head of Ansar Dine, which has ties to Al Qaeda\'s north African branch. Ag Ghaly once played a key role as power broker between government and Tuareg rebels and was sent by Toure as an adviser to the consulate in Saudi Arabia. His involvement in recent fighting emerged when a video was released in March showing dead and captured soldiers after a bloody attack on the town of Aguelhok, in which a spokesman introduces Ansar Dine, naming Ag Ghaly as their commander. Ag Ghaly is seen inspecting fighters and leading them in prayer and the group explains it aims to impose sharia, or Islamic law, on the country. The two fighting parties have ambiguous links but the MNLA has distanced itself from any religious demands. The region affected by the fighting is considered a key regional hub for weapons and drug trafficking. In a bid to consolidate their power, the junta have unveiled their own constitution. While they promise they will not run in future polls, no date for a return to democracy has been set. The European Union, the United States and other Western powers have cut off hundreds of millions of dollars of support to Mali -- except for emergency aid to drought-hit regions.