The bloc gives long-time ruler Yahya Jammeh a final chance to hand over power to newly-inaugurated President Adama Barrow.
A coalition of West African countries halted military action in Gambia late Thursday and gave Yahya Jammeh yet another deadline to transfer power to President Adama Barrow. The new president took oath earlier in the day in exile at Gambia's embassy in neighbouring Senegal.
Jammeh, who ruled Gambia since a 1994 coup, refused to accept what he called the flawed results of the December elections. Neighbouring West African nations had initially given him the deadline of Wednesday midnight to step down after which they started moving troops into Gambia to support Barrow, in a military intervention dubbed Operation Restore Democracy.
Jammeh now has until noon on Friday to step down.
Marcel de Souza, head of the Economic Community Of West African States (ECOWAS) commission, made up of 15 member-nations, told reporters even if Jammeh steps down, he will not be allowed to remain in Gambia. However, Jammeh can choose his country of exile if negotiations succeed.
The US State Department said on Thursday they support the West African bloc's military action in Gambia.
"We support it because we understand that the purpose is to stabilise a tense situation and to try to observe (sic) of the people of the Gambia. Obviously, we are going to stay in close touch," State department spokesperson John Kirby said.
The UN Security Council also back efforts made by ECOWAS to ensure Barrow assumes power.
At his swearing in, Barrow called for international and ECOWAS support to deal with Gambia's political crisis.
Gambia is one of the smallest West African states with a population of just over 1.8 million.