Yahya Jammeh has led Gambia for 22 years since taking power in a coup.
Gambian president-elect Adama Barrow said on Monday longtime leader Yahya Jammeh should leave power immediately after the incumbent president announced he would challenge the election result despite previously accepting defeat.
"I think he should step down now," Mr Barrow told AFP. "He has lost the election, we don't want to waste time, we want this country to start moving."
Mr Barrow is due to welcome a heavyweight group of African heads of state and UN representatives on Tuesday to persuade Mr Jammeh to go, which the President-elect said gave him hope that he would soon take power.
The high level delegation will include UN West Africa envoy Mohamed Ibn Chambas, Nigerian President Muhammadu Buhari, and Liberian leader Ellen Johnson Sirleaf in her capacity as head of the West African ECOWAS bloc, the Senegalese foreign ministry confirmed.
The delegation would "ask him to leave power", a source at the Senegalese foreign affairs spokesman said.
Mr Jammeh's swift concession of defeat had initially stunned observers and led to celebrations across the country.
But Mr Jammeh's party complicated what was expected to be a peaceful handover when it announced on Saturday that a legal complaint would be filed with the Supreme Court challenging the December 1 election result, as well as calling for new polls.
Outgoing Ghanaian President John Mahama is also expected to join the group on Tuesday, a regional example of a leader who just lost his own election but is nonetheless expected to hand power over without issue.
The delegation and international support "(is) giving us confidence and it will give confidence to every Gambian that the world is concerned about Gambia," Mr Barrow said.
'Reject the results in totality'
Mr Barrow urged Mr Jammeh to meet the heads of state when they arrive but could not confirm that the longtime leader would be present, saying that he had not spoken to him since December 2.
"I urge him and advise him to meet the international community. They are partners to The Gambia and The Gambia is a signatory to those institutions, so we have to give them that respect," he said.
Adding that his own safety was "a concern", Mr Barrow said he believed the army's declaration that he had top brass backing still held.
The President-elect said that Mr Jammeh's legal complaint over a vote recount was baseless and that he had no power to appoint to the Supreme Court new judges who would be necessary to hear the case. The court has sat dormant for more than a year.
"We don't have time to fight again. The Supreme Court wasn't existing for the last one year. There are a pile of cases that are waiting... but he doesn't care about it," Mr Barrow told AFP.
A readjustment of the votes counted in the election was made on Monday, reducing numbers of ballots for all three candidates but ultimately confirming Mr Barrow's victory.
In his speech on Friday, Mr Jammeh said he would now "reject the results in totality", and called for new elections.
Mr Jammeh has led the tiny sliver of a nation of just under two million people for 22 years since taking power in a coup.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)