BAMAKO, Mali - Rebels on Saturday attacked Mali's strategic northern city of Gao, a day after they took the provincial capital of Kidal, witnesses and an official said. The move deepens the crisis in the landlocked nation at the feet of the Sahara after a coup earlier this month by Malian soldiers angry at the government's handling of the rebellion.

The two towns are major prizes for the Tuareg rebels, who launched an insurgency in January fueled by the flow of arms from the fall of neighbouring Libya, where many of the rebels had been on the payroll of Moammar Gadhafi.

Gao is around 1,200 kilometres from the capital of Bamako, where junior officers overthrew the elected government and claimed power 10 days ago.

The countries neighbouring Mali have condemned the coup and have given the military junta a 72-hour deadline to hand power back to civilians, which expires on Monday, or face crippling sanctions. On Saturday, the junta sent a delegation to meet with the president of neighbouring Burkina Faso. The representative of the junta, Col. Moussa Coulibaly, told reporters afterwards that the junta delegation is "leaving feeling confident, and we hope we will quickly reach a consensus on how to restore the institutions of the state in a way that will be acceptable to the whole world."

However, a senior official of one of the nations neighbouring Mali said that he spoke by telephone on Saturday to coup leader Capt. Amadou Haya Sanogo and that the officer proposed that he should remain president during a transitional period leading up to elections. He added that he would head a government where all the other members would be civilians. The official, who could not be named because of the sensitivity of the matter, said that "his proposal is unacceptable. He must leave power immediately."

Sanogo claimed that he seized power because of the government's inability to handle the insurgency in the north. But since the March 21 coup, the rebels in the north have made significant advances.

A soldier at Gao garrison reached by telephone said heavy fighting continued Saturday afternoon and that the army had scrambled helicopter gunships that were bombarding rebel positions. A convoy of 14 army pickup trucks were seen retreating from the town, according to Sidi Amar, a resident of Gossi, around 160 kilometres from Gao.

If Gao falls, the only other major city in Mali's north in government hands is Timbuktu.

Baba Bore, a radio programmer at the local Radio Alfarouk station in the ancient city of Timbuktu, said gunshots were heard earlier in the day. The families of military members stationed at the city's two camps had evacuated. Checkpoints had been erected on all sides of Timbuktu.

Ivory Coast President Alassane Ouattara, the current chair of the Economic Community of West African States, or ECOWAS, said he has put 2,000 troops from West Africa on alert in order to deal with the situation in Mali. The regional body has threatened to use military force if the junta refuses to leave. On Saturday, Ouattara indicated that the bloc might be willing to use force to dislodge the rebels.

"Our wish is to avoid war," he said in an interview on Ivorian television. "We must do everything possible to preserve the territorial integrity of Mali."

The Tuareg rebels that have seized control of much of the north are a cloudy amalgam of different factions. They include a secular group known as the National Movement for the Liberation of Azawad, or NMLA, whose stated aim is to carve out a Tuareg homeland in the north. There is also an Islamic faction, called Ansar Dine, which says it wants to impose Sharia law in the north.

Already there are signs of disunity among the rebel groups. A man who fled Kidal across the border into Niger said the Islamist rebels from Ansar Dine had taken down all the flags of the NMLA in that city. He said the rebels were going around demanding shopkeepers take down posters considered to reflect Western culture. A hairdresser he was forced to remove photos of unveiled women that he displayed to show different hairstyles. The resident spoke on condition of anonymity for fear of reprisals against family members still in Kidal.

The nearly three-month-old insurgency has cost the lives of dozens of Malian soldiers who were sent to fight the separatists, often without enough ammunition. Last week, soldiers at a garrison in the capital began shooting in the air in a mutiny over the treatment of their brothers-in-arms.

The mutiny spread to other garrisons and by the evening of March 21, the country's democratically elected leader had fled the presidential palace and the soldiers led by Sanogo had grabbed the seat of government.

Mali is now facing severe economic sanctions over the coup. If the junta does not hand power to civilians by Monday, ECOWAS has said that they will close the country's land borders and freeze its account in the regional central bank.

Sanogo, the coup leader, has said that he "understands" the position of the regional body, but begged Mali's neighbours to deepen their analysis and to examine the reasons that led to the coup, especially the botched operations in the country's north that cost the lives of soldiers.

At a stadium in the capital, several hundred people were bussed in by political parties that are supporting the putschists for a rally in support of the coup. Mali was considered one of the few established democracies in the region, and last week's military takeover has erased 21 years of democratic gains.

Those supporting the coup say that Mali's democratic reputation is an illusion, pointing to the widespread corruption that characterized the toppled regime. They held up signs that said: "No to the facade of democracy."