The runner-up in Gambia's election, Ousainou Darboe, has launched a legal challenge to President Adama Barrow's victory, his party said on Monday.

Barrow won the Dec. 4 poll with 53 percent of the vote, well ahead of Darboe who got about 28 percent. The election was the first in 27 years without despotic former president Yahya Jammeh and was seen as a test of the tiny West African nation's fragile democracy.

The day after the poll, Darboe and two other candidates said they did not accept the results because the vote count took longer than expected, and because of alleged problems at polling stations.

They have yet to provide any evidence of wrongdoing.

"After our executive meeting on Friday with our lawyers we have decided to file a petition today at the Supreme Court," Almamy Taal, spokesman for Darboe's United Democratic party (UDP), told the press.

Taal did not set out the grounds of the complaint.

Election observers from the African Union said the election was conducted in line with international standards, and European Union observers praised the transparency of the voting and counting process.

(With input from agencies)