The Supreme Court of Gambia cannot rule on President Yahya Jammeh's challenge against his electoral defeat until May, according to its chief justice.
The ruling casts further doubt on whether a peaceful political transition will happen next week as scheduled.
The West African country has been thrust into a political crisis following a December 1 presidential vote, which saw longtime ruler Jammeh losing to opposition leader Adama Barrow.
Jammeh initially conceded defeat but later reversed his position, lodging a legal case aimed at annulling the result and triggering new elections.
Barrow, a former real estate agent, is scheduled to take office on January 19.
The election challenge was supposed to be heard on Tuesday by five judges, including Chief Justice Emmanuel Fagbele, but the Nigerian and Sierra Leonean judges were absent.
Fagbele told Jammeh's lawyers that he needed a full panel to hear the petition but the outsourced judges would not travel there until either May or November.
The Gambia relies on foreign judges to staff its courts due to a lack of trained professionals in the tiny country.
The legal case was adjourned to Monday, but Fagbele warned the petitioners that they should not expect anything different.
"We can only hear this matter when we have a full bench of the Supreme Court," Fagbele said.
His comments came as leaders from West African regional bloc, ECOWAS, pushed back from Wednesday to Friday a mediation mission in Banjul, the capital of Gambia.
Nigeria said the delay was at the "insistence" of Jammeh.
Maggie Dwyer, of the Centre of African Studies at the University of Edinburgh, says the postponement of the election challenge "buys Jammeh more time and places the pressure on ECOWAS to broker a deal".
Speaking to Al Jazeera, she said: "Without a significant deal reached, which would probably include amnesty for Jammeh and possibly senior military officers, it is very unlikely that there will be any transition next week.
"Jammeh will need a significant incentive and a way to save face in order for him to voluntarily leave office."
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The president has made clear he will not go until his complaint is heard, and, on December 20, he was broadcast on state TV saying "unless the Court decides the case, there will be no inauguration on the 19 January. And let me see what ECOWAS and those big powers behind them can do".
The West African bloc has previously said it has a military force on standby if Jammeh refuses to cede power when his mandate expires, with Nigeria's foreign minister saying on Monday the use of force remained an option if there was no movement in the situation.
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"The president is insisting that there'll be no inauguration until the court decides on his case. But the other camp is busy preparing for the inauguration," a Banjul-based analyst told Al Jazeera on condition of anonymity.
"So, on January 19, Barrow's camp will go out and President Jammeh will attempt to stop them. That's where the problem will be and that's why the role of ECOWAS will be crucial."
The court's announcement comes a day after Sheriff Bojang, the communications minister, stepped down and fled the country.
Will of the people
Bojang said he resigned because Jammeh's refusal to accept the outcome of the election was disregarding the will of the people.
Dwyer, of the Centre of African Studies, said defections by officials, such as Bojang, indicated that Jammeh was "becoming increasingly isolated" amid mounting pressure.
"Nearly all prominent organisations in the Gambia and the UN, AU, ECOWAS, US and more are unlikely to back down on their calls for Jammeh to concede defeat," she told Al Jazeera.
Additional reporting by Teo Kermeliotis: @Teo_Kermeliotis
Source: Al Jazeera and news agencies