In a sharp escalation after months of diplomatic tensions, leaders from the Economic Community of West African States (ECOWAS) on Sunday agreed to shutter borders with the Sahel state and impose a trade embargo.
The move came after Mali's interim government last month proposed staying in power for up to five years before staging elections -- despite international demands that it respect a promise to hold elections on February 27.
As well as shutting borders and imposing a trade embargo, ECOWAS also agreed to halt financial aid to Mali and freeze its assets at the Central Bank of West African States.
Mali's junta has condemned the measures, and urged Malians to stage nationwide demonstrations against them on Friday.
But France, Mali's former colonial power which also currently holds the European Union's rotating presidency, backed the sanctions.
"We are in complete solidarity with the region and with this very courageous and clear stance" by ECOWAS, French President Emmanuel Macron told reporters on Tuesday.
He added that the EU would seek to strengthen sanctions on the junta.
The US also hailed the "strong actions" by ECOWAS and said it shared the bloc's "deep disappointment" over the election schedule.
"We urge the transitional government to keep its pledge to the Malian people to return their country to democracy," said the US ambassador to the United Nations, Linda Thomas-Greenfield.
"A five-year transition is not in their interest and extends the pain of the people," she told a Security Council meeting.
The presidency of Algeria, which shares a long border with Mali, on Tuesday also called on the junta to negotiate with ECOWAS and "reach a plan to end the crisis, taking into account international demands and the legitimate demands of the Malian people".
So far, Mali's junta has remained defiant.
The country's strongman Colonel Assimi Goita, in an address late Monday, called the sanctions "illegitimate, illegal and inhumane", although he added that he remains open to dialogue with his West African neighbours.
The latest political crisis caps a period of steadily deteriorating relations between Mali and its neighbours and partners, which began after Goita led a coup in August 2020 that toppled president Ibrahim Boubacar Keita.
Under threat of sanctions following that putsch, Goita had promised to hold presidential and legislative elections, and to restore civilian rule by February 2022.
But the strongman staged a de facto second coup in May 2021, forcing out an interim civilian government and disrupting the timetable to restore democracy.
Goita also declared himself interim president.
Then in December, his government proposed staying in power for up to an additional five years.
It argued, among other reasons, that rampant insecurity in Mali prevents it from staging safe elections according to the agreed timetable.
The vast nation of 19 million people is in the grip of a jihadist insurgency, and swathes of territory are outside government control.
'Lack Of Political Will'
Goita has called for calm and "resilience" in the face of the ECOWAS sanctions and has assured Malians that the government will take steps to counter their effects.
Landlocked Mali is one of the poorest countries in the world.
The sanctions appear to have angered many in Mali, where pro-government messages, as well as criticisms of ECOWAS, have flooded social media.
Neighbouring Guinea -- an ECOWAS member also under military rule -- announced on Monday that it would neither close its borders with Mali nor block trade.
However, offering a rare rebuke of the junta, a group of about a dozen Malian political parties said on Tuesday that the military held sole responsibility for the sanctions.
"These sanctions are the result of a lack of political will on the part of the authorities to respect their commitments," the parties said.