Political veteran Joseph Boakai was on Monday declared the winner of Liberia's presidential election, beating incumbent George Weah, electoral authorities said after completing the ballot count.

Boakai won with 50.64 percent of the vote, against 49.36 percent of the vote for former international football star Weah, National Electoral Commission (NEC) president Davidetta Browne Lansanah told reporters.

Boakai won by a margin of just 20,567 votes.

Weah had already conceded defeat on Friday evening, based on the results of more than 99.98 percent of polling stations. 

The outgoing president won praise from abroad on Monday for conceding and promoting a non-violent transition in a region marred by coups.

"Liberians have once again demonstrated that democracy is alive in the ECOWAS region and that change is possible through peaceful means," the Economic Community of West African States said in a statement.

But hours after Boakai's victory was announced, a car ploughed into a crowd of supporters outside his party's headquarters, injuring at least 16 people, police said. His party said at least 10 people were killed in the incident.

Since 2020, ECOWAS states have seen abrupt regime changes with military forces seizing power in four of the fifteen member countries: Mali, Guinea, Burkina Faso, and Niger. 

The election six years ago of Weah — the first African footballer to win both FIFA's World Player of the Year trophy and the Ballon d'Or — had sparked high hopes of change in Liberia, which is still reeling from back-to-back civil wars and the 2014-2016 Ebola epidemic.

But critics have accused his government of corruption and him of failing to keep a promise to improve the lives of the poorest. 

While his party lost, "Liberia has won," Weah had said on the radio. 

Weah said he had spoken to the man he called the "president-elect" to congratulate him and urged his supporters to accept the election result.

"This is a time for graciousness in defeat," he said, adding: "Our time will come again". 

The African Union sent its congratulations to Boakai on Monday. 

AU chairman Moussa Faki Mahamat also called on "all parties to continue to display maturity and embrace dialogue to consolidate democracy". 

US President Joe Biden also sent congratulations to Boakai, while praising Weah for "respecting the will of the people, and putting patriotism above politics".

'Defied the stereotype'

The ECOWAS bloc said that the post-election phase was "crucial", and called on "the people of Liberia to maintain and safeguard peace and security".

However, the NEC head said that on Friday the commission had received two appeals from Weah's party concerning the conduct of the election in Nimba County. 

The commission has 30 days to investigate and reach a decision, she said. 

Former Nigerian president Goodluck Jonathan, who led a mediation mission for the election, said he was "deeply pleased with the successful outcome of the democratic process", in comments posted on X, formerly Twitter. 

He went on to congratulate Boakai, urging him "to be magnanimous in victory and seek to continue the efforts to unite" Liberia. 

Nigerian President Bola Ahmed Tinubu, who is a heavyweight in the West African bloc, commended Weah's concession saying it had averted any form of socio-political crisis. 

"He has defied the stereotype that peaceful transitions of power are untenable in West Africa," Tinubu said. 

Several presidential elections in the region are upcoming in 2024, including polls in Senegal, Ghana and Mauritania, as well as military-ruled Mali and Burkina Faso.