Mali's neighbours on Thursday gave the leaders of last week's coup 72 hours to begin handing back power to civilians or face a crippling closure of trade borders, diplomatic isolation and a freeze in funding from the regional central bank.
The West African country is an indirect victim of last year's conflict in Libya, from where weapons spilled out and bolstered a northern rebellion. The coup was led by soldiers who complain the government has not given them adequate means to fight off the uprising.
The border threat was announced to reporters in neighbouring Ivory Coast by the West African ECOWAS bloc after a delegation of five regional leaders were prevented from landing in Mali by a runway invasion at the airport in the capital Bamako.
The leaders, including Ivorian President and current ECOWAS chief Alassane Ouattara, did a mid-air U-turn and flew back to Abidjan where they issued an ultimatum to the officers behind the coup in what was one of the region's most stable democracies.
The following sanctions were agreed and shall be implemented within 72 hours by Monday, April 2, 2012 at the latest, ECOWAS commission president Desire Kadre Ouedraogo said.
He said the sanctions would include: the closure of the land-locked gold producer's borders for all but humanitarian goods; the freezing of Mali's account at the central bank of the West African franc zone and restrictions on its negotiations with private banks in the region; an asset freeze and travel ban on individual junta members.
In addition, steps would be taken to starve Malian traders of access to seaports and the countries of the 15-state region would recall their ambassadors from Mali.
The measures, if applied, could further damage the interests of international miners in Africa's third biggest gold producer. Uncertainty over the future has already pushed their shares lower on Western stock exchanges.
The threat underlines how seriously Mali's neighbours take a coup which they fear could trigger similar attempts in countries which between them have been blighted by decades of civil war and power grabs.
It was not immediately clear whether the leaders - from Ivory Coast, Niger, Benin, Burkina Faso, and Liberia - planned to make a new attempt to visit Mali's new junta on Friday.
FIGHTING IN THE NORTH
Their jet had been forced to turn back mid-flight after hundreds of supporters of the coup invaded Bamako's main runway.
It (the visit) was called off after the junta allowed demonstrators onto the tarmac, an ECOWAS official said, asking not to be named. Understandably this created a security scare forcing the heads of state to suspend their arrival.
Pro-junta protesters at Bamako airport, some carrying banners reading ECOWAS, let us solve our own problems and ECOWAS, shame of Africa, streamed onto the runway before junta leader Captain Amadou Sanogo persuaded them to leave.
Mali's coup, seen as a major setback to fragile democratic gains in Africa, was triggered by army anger at President Amadou Toumani Toure's handling of a Tuareg-led rebellion in north Mali that has gained ground in recent weeks.
Toure, president since 2002, was planning to hand over power following elections set for April.
The northern rebels, who are using weapons smuggled from ousted Libyan leader Muammar Gaddafi's arsenal to carve out a desert homeland, have said they plan to use coup chaos in Bamako to attack more towns, including Timbuktu.
A resident of Kidal, one of the biggest towns in Mali's north, told Reuters that heavy weapons fire had erupted on Thursday morning on the town's outskirts.
Later, Hohhomeny Belco Maiga, president of the regional Assembly for Kidal, said the fighting had eased but he did not expect a proper respite. The night will be long. They will not stop. They are determined, he said by phone.
(Additional reporting by Adama Diarra and Tiemoko Diarra in Bamako, Loucoumane Coulibaly in Abidjan, and Kwasi Kpodo in Accra; Writing by Richard Valdmanis; Editing by Diana Abdallah)