The ECOWAS has given Gambian incumbent President Yahya Jammeh a final opportunity to relinquish power after Senegalese troops entered his country.
Yahya Jammeh has been given until noon on January 20 to leave office or be forced out by UN-backed regional forces.
Troops have been told to halt their advance until the deadline passes.
The Economic Community of West African States (ECOWAS) is acting in support of Adama Barrow, who was sworn in as the new Gambian president on January 19.
Adama Barrow’s legitimacy as president, after winning last month’s election, has been recognized internationally.
Last-ditch mediation talks, led by Guinea’s President Alpha Conde, were due today. Mauritanian President Mohamed Ould Abdel Aziz is on his way to Banjul, and Alpha Conde is reported to be with him.
Chairman of the ECOWAS commission, Marcel Alain de Souza, said that if the meeting with Alpha Conde proved unsuccessful, military action would follow.
“If by midday, he [Yahya Jammeh] doesn’t agree to leave The Gambia under the banner of President Conde, we really will intervene militarily,” Marcel Alain de Souza said.
Troops from Senegal and other West African countries crossed into The Gambia after an initial deadline for Yahya Jammeh to stand down passed without his resignation.
Adama Barrow, who remains in Senegal, has said that he will not return to Gambia’s capital, Banjul, until the military operation has ended.
The threat by the West African regional bloc ECOWAS to remove Yahya Jammeh by force is supported by the 15-member UN Security Council, although the council has stressed that a political solution should be the priority.
In his inaugural speech at the Gambian embassy in Senegal’s capital, Dakar, President Adama Barrow ordered all members of The Gambia’s armed forces to remain in their barracks.
Any found illegally bearing arms would be considered “rebels”, he said.
Amid the crisis, the UN refugee agency reported that more than 45,000 people had fled The Gambia for Senegal so far in 2017.
More people could leave if the situation was not resolved, the UNHCR said.
After first accepting defeat in the election Yahya Jammeh reversed his position and said he would not step down. He declared a 90-day state of emergency, blaming irregularities in the electoral process.
The electoral commission accepted that some of its early results had contained errors but said they would not have affected Adama Barrow’s win.
Yahya Jammeh has said he will stay in office until new elections are held.
Remaining in power would also give Yahya Jammeh protection against prosecution for alleged abuses committed during his rule.