Jerome Delay, File, Associated Press
FILE- In this Friday Dec. 2, 2016 file photo, Gambians celebrate the victory of Opposition coalition candidate Adama Barrow, run past an army soldier on the streets of Serrekunda, Gambia. The United Nations secretary-general says a takeover by Gambia's security forces of the country's electoral commission offices could compromise "sensitive electoral material" as the president refuses to accept being voted out of power.

ABUJA, Nigeria — West African leaders at a summit Saturday discussed how to get Gambia's longtime ruler to accept an electoral defeat — and a military intervention was among the possible options.

Coup leader Yahya Jammeh shocked Gambians by conceding defeat after a Dec. 1 vote, then changed his mind and called for a new election. The United Nations, the United States and the African Union have all condemned the move.

Gambians "voted decisively for a change in the political leadership of the country," Liberian President Ellen Johnson Sirleaf, told the summit. Leaders must decide "measures to bring this matter to successful conclusion before Jan. 19" when Jammeh's mandate expires.

She is the chair of the Economic Community of West African States. Eleven presidents were at Saturday's summit in Abuja, Nigeria, with four absentees, most notably Jammeh.

Community President Marcel de Souza said this week a military intervention and "draconian measures" must be considered if diplomacy fails with Jammeh. He spoke in an interview with Radio France International.

Jammeh's defiance challenges the first regional community in the world to agree to military interventions in member states accused of abusing human rights and democratic principles. It has spent 25 years nurturing democracy in a region once prone to military coups.

Jammeh acted after an opposition coalition official in Gambia said he should be prosecuted for gross human rights abuses. Jammeh is accused of arbitrarily detaining, torturing and sometimes killing political opponents.

Jammeh used the excuse of errors in the vote tally, ignoring the insistence of the country's Independent Electoral Commission that the winner remains businessman Adama Barrow who won with a revised count of 227,708 votes to Jammeh's 208,487. Barrow says he now fears for his life.

The ruling party filed a court challenge against the election results Tuesday, a constitutional move complicated by the fact that Gambia's Supreme Court does not have a quorum. The United States said it doubts it is "a credible court dedicated to ensuring the integrity of Gambia's democratic process."

Jammeh on Tuesday sent troops to take over the electoral commission's office in Banjul, the capital, shortly before a delegation of West African leaders arrived on an inconclusive mission.

Jammeh seized power in a bloodless coup in 1994 in the country of 1.9 million people which is known for its beaches.

Faul reported from Lagos, Nigeria.