Senegal's forces are at the Gambian border and will enter at midnight if veteran Gambian President Yahya Jammeh refuses to leave power, Colonel Abdou Ndiaye, a spokesman for the Senegalese army, told Reuters.
Jammeh, who lost a Dec. 1 election to coalition leader Adama Barrow, said he will not step down, citing irregularities in the vote. His official mandate ends at midnight.
"We are ready and are awaiting the deadline at midnight. If no political solution is found, we will step in," Ndiaye said
The statement raises the prospect of armed confrontation between forces loyal to the president who has ruled Gambia for 22 years and Senegal, which is the only neighbour of the tiny country. Gambia is a territorial prominentary leading out from the west African coast and surrounded by Senegal.
Authorities took steps to shore up Jammeh's authority this week. Jammeh declared a state of emergency on Monday, while on Tuesday the National Assembly passed a resolution to enable him to remain in office for three months.
Gambia has had just two rulers since independence in 1965. Jammeh seized power in a coup and his government has gained a reputation among ordinary Gambians and human rights activists for torturing and killing opponents.
Few people expected him to lose the election and the result was greeted with joy by many in the country and by democracy advocates across the continent, particularly when Jammeh initially said he would accept the result and step down.
Barrow, who is in Senegal, was examining the implications of the assembly's resolution and the state of emergency, given the constitutional requirement for a handover and the need to maintain peace, his spokesman Halifa Sallah told Reuters.
Refugees Flee Gambia
Jammeh's decision to backtrack has unleashed turmoil in the riverine country. At least eight ministers have also resigned from his government.
At least 26,000 people have fled Gambia to Senegal fearing unrest, the U.N. High Commissioner for Refugees (UNHCR) said on Wednesday, citing Senegalese government figures.
"Up until the night of the 16th there were 26,000 people .... The flow has increased sharply since then," said Helene Caux, regional information officer for the UNHCR. She said up to 80 percent were children accompanied by women.
"Senegal has informed us that they have the capacity to take in 50,000 refugees in the short term and is making plans to accept up to 100,000," Caux said.
"People are afraid, we don't know what's going to happen," said a restaurant worker who gave only his first name, Musa, at an eatery in the capital Banjul normally buzzing but now empty of tourists.
"We hope he (Jammeh) will leave so this will be over quickly and things can get back to normal," he said.
Tour operator Thomas Cook started flying nearly 1,000 holidaymakers home on Wednesday. It said on its website it was laying on extra flights in the next 48 hours to remove 985 package tour customers.
It was also trying to contact a further 2,500 'flight only' tourists in Gambia to arrange for their departure on the earliest available flight, it said in a statement.
Gambia's economy relies on one main crop, peanuts, and tourism. Its beaches are popular with European holidaymakers seeking a winter break.