The UN has stopped The Gambia's controversial army chief from visiting troops serving as peacekeepers in Darfur, as international pressure grows on the country's top brass to accept incoming president-elect Adama Barrow.

Gambian security forces seized the country's Independent Electoral Commission on Tuesday, drawing international condemnation follosing a contested presidential election held on December 1.

President Yahya Jammeh, who initially conceded defeat, has now lodged a Supreme Court case to challenge the result.

A diplomatic source told AFP there were "serious concerns about this visit given the situation in Banjul, especially after the takeover of the election commission's office".

"The UN has decided to cancel General Badjie's visit to Gambian peacekeepers in Sudan," the source added.

Badjie has flip-flopped over his loyalty to Jammeh or Barrow.

Barrow, who should be inaugurated in January, claimed Badjie had personally assured him of his support.

But the general then appeared on Tuesday at high-level mediation talks in Banjul wearing a badge with Jammeh's face on it, and told journalists the incumbent was his boss.

Human Rights Watch has said it is "crucial that (security forces) act in a politically neutral and professional manner".

There are 213 Gambian military personnel deployed in Darfur, Sudan as part of the UN peacekeeping force stationed there.

Elsewhere on Friday Senegalese President Macky Sall, whose nation almost entirely surrounds The Gambia, said a military intervention had to be the final course of action if Jammeh refuses to go.

"The recourse to force must be the last step, only if diplomacy has completely failed," Sall told French television channel France 24.

Sall also mooted the idea of potential protections for Jammeh if he agreed to leave.

"Justice must be served but in the name of peace we must also be able to find compromises," Sall said.

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