West African leaders are to head to Gambia to try to persuade incumbent President Yahya Jammeh to agree “to leave office” after his defeat at the ballot box, according to a Senegalese foreign ministry source.

The delegation headed by Liberian leader Ellen Johnson Sirleaf, a Nobel Peace laureate and the current chairwoman of the Economic Community of West African States (ECOWAS), will include Nigerian President Muhammadu Buhari, Sierra Leone leader Ernest Bai Koroma and outgoing Ghanaian President John Dramani Mahama.

“These leaders will ask him to leave office,” the source said.

Mankeur Ndiaye, Senegalese foreign minister, said an ECOWAS delegation was previously due in Banjul last week but Jammeh did not allow them to visit.

Gambian presidential election: Yahya Jammeh demands new vote

Celebrations erupted across the West African nation last week when Jammeh unexpectedly conceded defeat after the elections commission announced the victory of opposition candidate Adama Barrow.

However, in a dramatic about-face that drew international condemnation, the former coup leader on Friday decried “serious and unacceptable abnormalities” and called for fresh polls.

In a statement broadcast on state television late on Saturday, Jammeh’s Alliance for Patriotic Reorientation and Construction (APRC) party said it was preparing a petition “against the flawed decision of the Independent Elections Commission”.

The deadline for submitting a challenge to the court is Tuesday.

Barrow is due on Tuesday to welcome the ECOWAS leaders along with a delegation of UN representatives, which the president-elect said gave him hope that he would soon take power.

Sirleaf said over the weekend that the reversal of Jammeh’s decision “threatened pe...