West African leaders have given Yahya Jammeh, who lost elections last month, until midday on Friday to hand over power and agree to leave The Gambia or face military action carried out by the regional bloc Economic Community of West African States (ECOWAS).

West African troops entered the country to bolster its new President Adama Barrow - who was sworn-in on Thursday - but military operations were suspended a few hours later in favour of a final diplomatic push to convince Jammeh, who has stubbornly refused to quit, to exit the country.

"We have suspended operations and given him an ultimatum," said Marcel Alain de Souza, head of the 15-nation ECOWAS.

"If by midday he doesn't agree to leave The Gambia ... we really will intervene militarily."

Final talks were being led by Guinean President Alpha Conde in Gambia's capital Banjul on Friday morning, according to de Souza.

De Souza said a total of 7 000 troops were mobilised by Senegal and four other nations that had crossed into the tiny tourist-friendly country on Wednesday.

Support for the long-ruling leader has been crumbling. The army chief joined ordinary citizens celebrating in the streets on Thursday seven weeks after contested polls.

"Diplomacy is a long road - it always has been and always will be so every opportunity to find a resolution is the best means possible for the region,"

Robin Sanders, a former US ambassador to ECOWAS, told Al Jazeera.

"The last thing that West Africa needs is another conflict."

While there has been talk that a deal may include amnesty for Jammeh, whose regime has been accused of various human rights abuses, Sanders said this would set a bad precedent.

"Also in this case, I am not in the camp of complete amnesty because what you do is signal additional impunity going forward with other leaders, not only just in the continent but across the world," she said.

Barrow was sworn in at The Gambia's embassy in Dakar in neighbouring Senegal on Thursday. Celebrations erupted in Banjul, meanwhile, where tensions have run high over the crisis, especially since the declaration of a state of emergency by Jammeh made on Tuesday.

Barrow, a real-estate agent turned politician, had flown into Senegal on January 15 to seek shelter after weeks of rising tension over Jammeh's stance.