(CNN) Gambia's outgoing President Yahya Jammeh should have spent his last day in office Wednesday but he has refused to accept defeat in last month's election and hand over power to victor Adama Barrow, whose inauguration is due Thursday.

Jammeh's rejection of the results of the December 1 election has thrown the small West African nation into political turmoil, alarmed its neighbors and prompted concern for foreigners in the country.

Here's what you need to know about what's happening in Gambia:

What's the current situation?

Troops from several West African countries are on standby to enter Gambia if Jammeh insists on staying in the post.

Barrow said he would be inaugurated Thursday at Gambia's embassy in neighboring Senegal.

Jammeh declared a state of emergency a day before his mandate was due to end, saying that "a situation exists which, if it is allowed to continue, may lead to a state of public emergency." He blamed an "unprecedented and extraordinary amount of foreign interference" for the crisis.

In a televised address, Jammeh said an application had been filed at the Supreme Court for an injunction to prevent Barrow from being sworn in before the court can hear his petition contesting the election results.

Gambian President-elect Adama Barrow is due to be inaugurated Thursday.

The long-serving leader said "any acts of disobedience" were banned under the state of emergency and that Gambian security forces were "instructed to maintain absolute law and order throughout the country."

Reuters news agency reported Wednesday that Gambia's National Assembly had passed a resolution allowing Jammeh another 90 days in power.

What about Barrow?

Barrow has declared himself determined to be inaugurated as scheduled, if not in Gambia itself.

You are all welcome to my inauguration today 4pm at The #Gambian embassy in #Dakar. — Adama Barrow (@BarrowOfficial1) January 19, 2017

"You are all welcome to my inauguration today 4pm at The #Gambian embassy in #Dakar," he posted on his official Twitter account.

Barrow, a property developer who won 45% of the vote, has said that Jammeh has no authority to reject the election result.

The President-elect's office insisted in a statement that "the exercise of right to file an election petition by the loser does not deprive the winner the right to prepare for his inauguration."

His office accused Jammeh of using the court case to mobilize his supporters by making them feel cheated of victory and said this "is contributing to the fear that he is not ready for a peaceful transfer of power."

It also called for the "general (mobilization) of the people for the inauguration."

How did Gambia get to this point?

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Jammeh suffered a shocking loss after running for his fifth term. After initially conceding defeat in a televised address, a week later he announced his "total rejection" of the outcome and said new elections would be held.

"We will go back to the polls because I want to make sure that every Gambian has voted under an independent electoral commission that is independent, neutral and free from foreign influence," he said.

Since then, he has remained intransigent despite mediation attempts by leaders from ECOWAS, and calls by the wider international community and the United Nations for him to respect the election results.

What kind of leader is Jammeh?

Jammeh seized power in a 1994 military coup. Human rights groups have described his regime as abusive, with hundreds of political prisoners languishing in jail.

Protesters hold placards supporting Gambia's election results last month in Dakar, Senegal.

Gambia is the fourth largest source of migrants arriving in Italy despite having a population of fewer than 2 million.

Earlier this month, Amnesty International and Human Rights Watch issued a joint statement accusing Jammeh's government of arresting opposition supporters arbitrarily and closing down three independent radio stations.

"The targeting of the #Gambiahasdecided movement and the closure of private radio stations threaten the rights of Gambians to express their opposition to Jammeh's attempt to stay in power," said Jim Wormington, West Africa researcher at Human Rights Watch. "It's at times like this that free expression is most crucial."

What's the international reaction?

Regional leaders could use force to resolve the situation if Jammeh doesn't go willingly.

Jammeh, left, meets with Nigerian President Muhammadu Buhari on Friday in Gambia's captial, Banjul.

Senegal, Ghana, Togo and Mali are among the countries who have contributed to the military effort, while the Nigerian air force said 200 of its troops would join forces from ECOWAS.

On Wednesday, Col. Seydou Maiga Moro of ECOWAS told Senegal's state media that his forces were waiting to act.

The head of the UN West Africa office told the UN Security Council on January 13 that a high-level delegation was in Gambia that day to persuade Jammeh to step down, and that it would "leave no doubt about the determination of ECOWAS to use all necessary means, including force, to have the will of the Gambian people upheld."

Jammeh said he had spoken with Liberian President Ellen Johnson Sirleaf, chairwoman of ECOWAS, and confirmed his "continued commitment to the peaceful resolution of our political situation."

What has the United States said?

US State Department spokesman John Kirby said Jammeh was "losing opportunities to respect the will of the Gambian people and to peacefully hand over power to the President-elect" as scheduled.

"Doing so would allow him to leave office with his head held high and to protect the Gambian people from potential chaos. Failure to do so will put his legacy -- and, more importantly, the Gambia -- in peril, and we have been clear about this," he told a press briefing.

Immediately after Jammeh called for fresh elections last month, the State Department described his action as "a reprehensible and unacceptable breach of faith with the people of the Gambia."

How are the Gambian people affected?

Facing uncertainty, people in Banjul head to a ferry Tuesday destined for Senegal.

Tens of thousands of Gambians, many of them children, are reported to have fled their homes amid fears of political violence, some heading to rural Gambia and others into Senegal.

Aid organization Save the Children warned of the risk of a humanitarian emergency on both sides of the border if fighting erupts.

"These children are largely fleeing to parts of both Gambia and Senegal where public services such as health facilities and schools are already under a great deal of strain," said Save the Children's Senegal country director Bonzi Mathurin.

Carla Fajardo, of Catholic Relief Services, told CNN that international humanitarian groups and local partners were preparing for different scenarios and had "positioned help for emergency intervention depending on what unfolds."

Aid groups will be providing assistance to women, children and the elderly, said Fajardo. The groups will also help families hosting those who are displaced, she said.

What's the impact on foreigners?

Amid the uncertainty, the UK Foreign Office updated its travel advice to caution against all but essential travel to Gambia. The country is a popular "winter sun" destination for Europeans, and tourism is a key industry there.

Tourists lie on the beach in Gambia's capital this week.

"The potential for military intervention and civil disturbance is high and could result in Banjul International Airport being closed at short notice," the Foreign Office said.

Tourists leave a hotel Wednesday in Banjul after a state of emergency went into effect.