The UN Security Council is set to vote later on Thursday on a draft resolution endorsing the West African regional force's efforts to remove outgoing president Yahya Jammeh who has refused to step down.
Adama Barrow has been sworn in as Gambia's new president on Thursday in a hastily arranged ceremony at Gambia's embassy in Senegal.
The small embassy room held about 40 people, including Senegal's prime minister and the head of Gambia's electoral commission.
A jumbo TV screen broadcast the swearing-in ceremony to several hundred watching outside the embassy.
"This is a day no Gambian will ever forget," said Barrow, dressed in a flowing white robe.
He called on all Gambians and the country's military to support his presidency.
"Our national flag will now fly high among the most democratic nations of the world. There is no loser in this election. One Gambia, one people, one nation."
Barrow ordered Gambia's armed forces to remain in their barracks and called for "allegiance to the motherland."
But the incumbent Yahya Jammeh has refused to step down after last month's presidential election.
Jammeh this week announced a state of emergency which the national assembly approved, keeping him in power for another 90 days.
West African countries have sided with the president-elect after Barrow won the December election.
The African Union and West African regional body ECOWAS (Economic Community Of West African States) have said that as of Thursday they will only recognise Barrow as Gambia's president and have threatened to invade Gambia to force outgoing president Yahya Jammeh to step down.
TRT World's Fidelis Mbah has more details.