Heavy fighting was reported in Gao on Saturday as the separatist rebels entered in trucks loaded with heavy weaponry.

The attack came a day after the rebels seized the city of Kidal, one of the north's three major regional centers - along with Gao and the ancient trading city of Timbuktu.

"I saw them entering the town itself and putting up their Azawad flags," a reporter for the news agency Reuters said, referring to the northern desert territory which the rebels want to make their homeland.

"People here are running all over the place, and all the shops are closing," the reporter said.

Regional governor's aide Mahamane Diakite was reported by the AFP news agency as saying he had heard heavy gunfire in the city and that he had seen two army helicopters taking off to try to combat the rebel advance.

Coup leaders on defensive

Tuareg rebels launched an insurgency in January, with the conflict costing the lives of dozens of Malian soldiers.

Soldiers in the capital, Bamako, overthrew the government on March 21, claiming the country's democratically-elected president had made mistakes in its response to the rebellion.

Since then, the rebels - who want a separate homeland in the vast northern desert province of Azawad - have made dramatic advances. On Friday, coup leader Captain Amadou Sanogo pleaded for help from the outside world to preserve the territorial integrity of the former French colony.

A delegation of Sanogo's junta arrived in Burkina Faso on Saturday for talks with President Blaise Compaore, who has been appointed mediator between the Malian military and the Economic Community of West African States (ECOWAS).

Leaders across West Africa have warned that borders surrounding the landlocked country will be closed unless the military engages in dialogue over a restoration of Mali's constitutional order.

Gao is the military headquarters of northern Mali, some 1,000 kilometers (650 miles) northeast of Bamako, and has a population of about 90,000.

rc/nk/tj (AP, AFP, Reuters)