"The electoral commission has violated the law and opposition leader Adama Barrow is not duly elected or returned as president [ .. ]  the election is void," a filing seen by the French new agency AFP said.

Jammeh last week announced his intention to challenge the election results. The 51-year-old, who has ruled the West African country for 22 years, had earlier conceded defeat to Adama Barrow, but then called armed military and police officers on to the streets of the capital Banjul.

Changing his mind

Security forces on Tuesday blocked the entrance to the electoral commission in Banjul, as outgoing President Yahya Jammeh refused to accept that he lost the presidential polls.

Security forces loyal to Jammeh surrounded the commission's offices and barred anyone from entering, staff said.

The move appeared to be linked to Jammeh's announcement on Saturday that he planned a legal challenge to the election results, which he had previously said he would abide by.

The chair of the electoral commission, Alieu Momarr Njie, called on Jammeh to admit defeat but was refused entry to his offices, the secretary general of The Gambia Press Union, Saikou Jammeh, told the German press agency DPA.

Army on board

The Gambia's chief of defense staff, Ousman Badjie, told local journalists he would remain loyal to Jammeh, indicating that the country's military would help the autocrat stay in power.

Barrow was initially supposed to take power in January.  Technically, the president does not have to relinquish power until then.

Military intervention?

Military intervention in The Gambia is "possible" if Jammeh does not step down after having lost elections, the head of the West African regional bloc Ecowas said on Tuesday.

Earlier on Tuesday, an African Union (AU) delegation arrived in Banjul, hoping to persuade Jammeh to accept his loss and hand over power to Barrow. The delegation was also expected to conduct talks with the Barrow and members of the opposition coalition, which supported his bid for the presidency.

The AU "strongly rejects any attempt to circumvent or reverse the outcome of the presidential election held in The Gambia ..., a clear expression of the popular will and choice of the Gambian people," the organization said in a statement.

Diplomacy was the preferred path, but "draconian" measures would have to be considered if it failed, Marcel de Souza told France's RFI radio station.

Asked whether Ecowas would consider sending troops into The Gambia, De Souza told Radio France Internationale: "We have done it in the past. We currently have troops in Guinea-Bissau with the Ecomib mission. We have had troops in Mali. And therefore it is a possible solution."

The leaders of Nigeria, Ghana, Liberia and Sierra Leone (president Ernest Bai Koroma pictured above) all arrived earlier in Banjul as part of a delegation seeking to persuade Jammeh to step down.

jh/jm (AFP, dpa)