BRAZZAVILLE: Denis Sassou Nguesso has won another seven years in power in the oil-rich Republic of Congo, which he has ruled for some 25 years, in a vote opponents have termed a giant fraud.

Sassou Nguesso won 78.61 percent of the votes cast in Sunday's poll where the turnout was 66.42 percent, Territorial Administration Minister Raymond Mboulou said Wednesday, reading out provisional figures.

Independent candidate, Joseph Kignoumbi Kia Mboungou, came in a distant second with 7.46 percent of the ballot.

Sassou Nguesso, a former military ruler, was said to have trounced 12 other candidates, six of whom had asked for a boycott of the poll on the grounds it would be rigged.

An exultant Sassou Nguesso told hundreds of supporters: "Today Congo is celebrating the victory of democracy in peace and harmony.

"In peace, freedom and transparency, in the presence of international observers, you have with the July 12 vote renewed your confidence in me," the 66-year-old leader said, promising to be the president of all Congolese.

Former finance minister Mathias Dzon, who had been considered Sassou Nguesso's main rival, took a mere 2.30 percent of the votes, the provisional results showed.

In third place was Nicephore Fylla de Saint-Eudes of the Liberal Republican Party with 6.98 percent.

Small teams of monitors from the African Union and the 10-nation Economic Community of Central African States gave the election a clean bill of health.

"The electoral campaign took place in a calm and serene atmosphere," they said in a joint statement.

However the non-governmental Congolese Observatory of Human Rights said the poll had been badly marred by "fraud and irregularities."

The opposition tried to stage a protest march after the results were announced but were stopped by the police, who said it had not been authorised.

"We just wanted to stage a peaceful demonstration with our supporters when the police started firing tear gas bombs," Emmanuel Ngouelondele, president of the Party for Democratic Alternance (PAD), told AFP.

Police had fired live rounds, injuring some of the demonstrators, he claimed, without elaborating. But police spokesman colonel Jean-Aive Alakoua denied the allegation.

Between 300 and 500 people took part in the attempted march, witnesses said.

Several opposition leaders who called for a boycott of the polls said on Wednesday that police had prevented them from holding a press conference in Brazzaville on the grounds that it was an unauthorised "public rally."

"It was a public meeting which was subject to authorisation," Congolese police spokesman Colonel Jean-Aive Alakoua told AFP, without giving further details.

Earlier, Dzon had said the meeting would allow some candidates to decide whether to recognise the election result and denounce any cheating that might have taken place.

Sassou Nguesso is one of Africa's longest-serving leaders having first come to power three decades ago.

His first stint as president of the former French colony stretched from 1979 to 1992 and he returned to the presidency in 1997 after a civil war.

He was re-elected in 2002 in a vote that international observers said fell short of democratic standards.

Some of Sassou Nguesso's opponents have said only about 10 percent of voters cast their ballots.

Official figures released from the capital Brazzaville, the oil city of Pointe Noire, and other regions in the interior of the country however showed turnout rates of between 40 and 92 percent.

"The population, feeling unsafe, was afraid and didn't turn out in large numbers," said Loamba Moke, president of the Association of Human Rights and for Prisoners (ADHUC).

The ADHUC was one of the local organisations that reported a high abstention rate.