The Gambia's president-elect Adama Barrow is to remain in Senegal until his planned inauguration on Thursday, state media in Senegal say.
The move was requested by West African leaders after a Mali summit, APS said.
President Yahya Jammeh, who initially admitted election defeat, says he will not step down until May, when the supreme court can hear his challenge.
Regional bloc Ecowas wants the UN to approve military action if Mr Barrow's inauguration on Thursday is blocked.
On Saturday leaders repeated their calls for Mr Jammeh to go voluntarily at an Africa-France summit in Bamako.
Mali's president Ibrahim Keita called for "proverbial African wisdom" to prevail to avert a bloodbath and there are growing fears that the uncertainty could cause a refugee exodus.
Thousands of Gambians, mostly women and children, have already crossed the border into neighbouring Senegal and further afield to Guinea-Bissau, where they do not require a visa, officials say.
Mr Barrow, who beat Mr Jammeh in last month's election, was at the Bamako summit and was referred to as the president.