The leaders of Guinea and Mauritania have arrived in Gambia's capital in a last-ditch diplomatic effort to get defeated president Yahya Jammeh to cede power.
The leaders arrived in Banjul as a noon deadline passed for Jammeh to give way, and a regional military force was awaiting orders.
The West African regional force, including tanks, moved into Gambia on Thursday evening and met no resistance. Its head said the troops will force Jammeh out if he does not step aside.
The force, including troops from Senegal, Ghana, Nigeria, Togo and Mali, charged into Gambia after the inauguration of Adama Barrow as the country's new president and the UN Security Council voted to approve the military intervention.
Mr Barrow, who won Gambia's presidential election in December, was sworn into office at the Gambian embassy in neighbouring Senegal, where he is staying for his safety.
Senegalese military spokesman Colonel Abdoul Ndiaye confirmed on Friday that the regional force had given Jammeh until noon to step down but would then resume its mandate to force him from power.
Jammeh remains in the official State House residence in Banjul.