Banjul - Gambian President Yahya Jammeh has fired 12 ambassadors after they called for him to step aside and allow opposition leader Adama Barrow to take power, a foreign ministry source told AFP on Monday.The Gambia's ambassadors to China, Britain, Turkey, Senegal, and the United States, as well as the country's permanent representative to the United Nations, were among those sacked after sending a letter asking Jammeh to leave in late December."The Gambia government has recalled 12 ambassadors after terminating their services," a foreign ministry source told AFP on condition of anonymity."I do not know why President Yahya Jammeh terminated their services, but I can tell you that these are the ambassadors that congratulated and endorsed President-elect Adama Barrow for his election victory," the source added.The ambassadors' actions highlight the isolation in which Jammeh finds himself a day ahead of his Supreme Court case against the Independent Electoral Commission (IEC), seeking to have the December 1 vote result overturned.Meanwhile on Monday, West African leaders were meeting in Abuja to decide on next steps in their mediation of The Gambia's political crisis, following top-level talks in Banjul last month that ended without resolution.Manipulation of ballot counting Jammeh and his political party have now lodged three separate legal complaints with the Supreme Court alleging manipulation of ballot counting by the IEC and intimidation of supporters.Gambian legal expert Aziz Bensouda said a quick resolution was unlikely and constitutionally Jammeh still had to step down by the end of his five-year mandate on January 18."In the absence of a court and the pure impossibility of the parties being served in time to appear and enter a response, it seems that an adjournment of the case will be the most likely outcome," he told AFP.Nigerian and Gambian legal experts told AFP that although five Nigerian judges and one from Sierra Leone had been invited to hear the case, none had responded.Jammeh's own lawyer Edward Gomez said he did not know himself how many judges would appear on the day."Judges have been employed for the Supreme Court, they have been appointed," he told AFP by phone. "Now whether they are here or they are not, I am in no position to tell you."Chief justice Emmanuel Fagbenle is the panel's only sitting judge, as the Supreme Court has lain dormant since May 2015. Several judges were fired after they commuted the death sentences of former military officers to life imprisonment.