Mali's military leaders have been given 72 hours to hand back power to the civilian president they toppled in a coup last week or face a crippling closure of trade borders and diplomatic isolation.
The proposed sanctions, which also include a freeze in funding from the regional central bank, were announced on Thursday at a news conference in neighbouring Ivory Coast by ECOWAS, the West African bloc.
The move came after a delegation of five regional leaders were prevented from landing in Mali by a runway invasion at the airport in Bamako, the capital.
The leaders, including Alassane Ouattara, the Ivorian President and current ECOWAS chief, did a mid-air U-turn and were forced to fly back to Abidjan where the ultimatum was issued.
"The following sanctions were agreed and shall be implemented within 72 hours by Monday, April 2, 2012 at the latest," said Desire Kadre Ouedraogo, the president of the ECOWAS commission.
He said the sanctions would include the closure of the land-locked gold producer's borders for all but humanitarian goods.
Mali's account at the central bank of the West African franc zone would also be frozen and restrictions placed on its negotiations with private banks in the region. An asset freeze and travel ban on individuals linked to the coup would also be imposed, said ECOWAS.
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 military takeover has destabilised one of the region's most stable democracies, with clashes reported between coup supporters and those who want power returned to civilian rulers.
On Friday, Captain Amadou Sanogo, the coup leader, appealed for external help to fight the insurrection in the north, warning that the situation there was "critical".
The West African country is an indirect victim of last year's conflict in Libya, from where weapons spilled out and bolstered the rebellion led by the Tuareg.
The coup was led by soldiers who said they were unhappy with the government's failure to arm and equip them to fight off the uprising.
If applied, the measures 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 US voiced disappointment after protesters prevented the ECOWAS delegation from landing and 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.
"We support their efforts to achieve a swift return to civilian rule in Mali," said Mark Toner, a spokesman at the US state department.
An ECOWAS official said the visit was called off after soldiers supporting the coup "allowed demonstrators onto the tarmac".
"Understandably this created a security scare forcing the heads of state to suspend their arrival," said the official who declined to be named as he was not authorised to speak to the media.
Pro-coup 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 Sanogo persuaded them to leave.
Mali's military ousted the democratically elected government of President Amadou Toumani Toure who came to power in 2002. Toure, who is said to be safe in Bamako, was planning to hand over power following elections set for April.
The Tuareg rebels in the north, who are trying to to carve out a desert homeland, have said they plan to use the coup chaos in Bamako to attack more towns, including the historical town of Timbuktu.