Angola's electoral commission on Monday declared the ruling MPLA, in power for nearly five decades since independence, the winner of last week's national election, handing President Joao Lourenco a second term amid concerns about possible fraud.

The commission gave the ex-Marxist People's Movement for the Liberation of Angola (MPLA) a 51.17% majority after all votes were counted. Its longtime opponent, the National Union for the Total Independence of Angola, or UNITA, got 43.95%, its best result ever.

Fewer than half of Angola's registered voters turned out for Wednesday's election which, despite being the closest fought yet, extends the rule of the MPLA that has ruled since independence from Portugal in 1975 and defeated UNITA in a long civil war.

UNITA leader Adalberto Costa Junior has rejected the results, citing discrepancies between the commission's count and the main opposition coalition's own tally.

Analysts fear any dispute could ignite mass street protests and possible violence among a poor and frustrated youth who voted for Costa Junior.

"The international community perceives this election as being free, fair and transparent," Lourenco told a news conference after the final results.

He promised more jobs for the young, in a country where half of under-25s are jobless and few feel the benefit of its vast oil wealth.

CONCERNS OF FRAUD

Local observers said the elections were free. International observers from the Southern African Development Community said the vote was calm and peaceful, but noted an insufficient number of local observers.

The head of the Community of Portuguese Language Countries (CPLP) election observers' mission, Jorge Carlos Fonseca, a former president of Cape Verde, told CNN Portugal that the mission's initial assessment did not say the vote was fair and free.

He said that around 2.7 million deceased people were included in the electoral roll, party delegates at polling stations did not have access to the roll and some candidates were given more air time than others.

A European Union spokesperson said in a statement the election was conducted in a "peaceful environment" but said it was aware of complaints by the opposition and civil society on "some shortcomings in the electoral process".

It said stakeholders should use all "legal remedies to address their concerns" and urged authorities to "make every possible efforts to respond to them in a fair and transparent manner".

With a new, centralised vote-counting system, first provisional results were announced just hours after polling stations closed, and the final tally was available a few days later, in what was the fastest result ever.

'RESOLVE GRIEVANCES'

If Costa Junior decides to dispute the result, he must lodge a complaint with the electoral commission. If that is rejected, he can challenge the result in the Constitutional Court, which must rule within 72 hours.

He has urged his supporters to remain calm.

The MPLA and UNITA, formerly anti-colonial guerrilla groups, were on opposing sides of a civil war since independence in 1975 until 2002, when Angolan troops killed UNITA's rebel leader, Jonas Savimbi.

The U.S., which backed UNITA in the civil war, called on all parties to "express themselves peacefully and to resolve any grievances in accordance with applicable legal processes under Angolan law".

"We will continue to closely follow the electoral process," said U.S. State Department deputy spokesperson Vedant Patel.

Despite losing the election, UNITA has nearly doubled to 90 its seats in the 220-seat parliament, for the first time depriving the MPLA of the two-thirds majority needed to pass major reforms. The ruling party will need the backing of opposition lawmakers to pass legislation.

UNITA won in Luanda, Angola's most populous province, and in Cabinda and Zaire, the provinces which produce most of the country's oil.

The final tally came a day after the funeral of Angola's long-serving ex-ruler and MPLA stalwart, Jose Eduardo dos Santos, who died in Spain in July.

Lourenco, 68, has pledged to press on with reforms in his second term, including privatising poorly run state assets and continuing to clean up corruption after investigating wealthy and powerful members of the Dos Santos family. .

But his reforms have so far failed to create a fairer distribution of Angola's vast oil wealth, which remains mostly in the hands of a few well-connected MPLA officials.