BAMAKO (Reuters) - Malian President Ibrahim Boubacar Keita won a landslide victory in a run-off against opposition rival Soumaila Cisse, the government said on Thursday, giving him a second term to try to turn back a surge in ethnic and Islamist militant violence.

Keita won 67 percent of the vote in an election marred by militant attacks and claims of fraud by the opposition.

Keita, known as IBK, now faces the giant task of lifting Mali out of a spiral of Islamist and ethnic bloodshed in the center and north, where attacks worsened in the months leading up to the vote despite the presence of a United Nations peacekeeping force and French troops.

The security situation and the militants’ ability to spread their influence to other West African countries is a concern to Western powers. Mali is also a main transit point for migrants trying to reach Europe via North Africa’s shores, a priority issue in EU capitals.

Threats by jihadists forced nearly 500 polling stations - about two percent of the total - to stay closed during Sunday’s run-off, the Ministry for Territorial Administration said. One election official was killed in northern Niafunke, in Timbuktu region.

Voter turnout of more than 2.7 million people was a muted 34 percent of the electorate.

A crowd of about 200 people danced and sang inside Keita’s campaign headquarters after the result was announced on state television.

“I am very happy, there is nothing to say, the gap is huge, the opposition must understand that there is no match,” said Tambours Adizatou Sogoba, a Keita supporter. “He has another five years, he will make Mali an emerging country.”

A few hundred meters away at the headquarters of opposition leader Cisse, about 40 supporters carrying placards reading “hands off my vote” and “respect the Malian vote” echoed Cisse’s complaints this week that he had won but IBK’s camp cheated by ballot stuffing and tweaking electoral rolls.

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Tiebele Drame, Cisse’s campaign manager, said: “The result does not reflect the truth of the polls, it does not reflect the Malian vote”.

He said the poll was rigged and a “manipulation of the vote”. Cisse had accused Keita of failing to get a grip on the violence and of allowing corruption to flourish.

But Keita’s campaign manager, Bocary Treta, said: “It is a victory for the Malian people. International observers were stationed all over and they paid tribute to the quality of the vote.”

The European Union observer mission and other local and international monitors have said that although there were irregularities and disruptions, they saw no evidence of fraud.

Cisse supporters were still not satisfied.

“We will take to the streets and reclaim our victory, the victory of the Malian people,” said one, named Yeri Bocoum said.

INSECURITY

The streets of Bamako remained calm on Thursday amid an internet shutdown. The government did not respond to queries about the cause of the network outage that cut social media and email access over Thursday morning.

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In other African countries including Gabon, Gambia and Cameroon, internet cuts have been used as a tool by governments to halt communications during elections or times of unrest.

Keita has more to worry about than the internet. Economic growth in Mali, a gold and cotton producer, has averaged five percent since he took power, and exports have increased, but Mali is still one of the poorest countries in the world. An estimated 60 per cent of the population lives below the poverty line, according to the United Nations.

Insecurity has worsened to the point of lawlessness in much of its huge northern desert.

In the past three years, attacks by jihadists with links to Islamic State and al Qaeda have tripled in Mali and violent deaths doubled, according to the civil society website Malilink.

French forces intervened to beat back a Tuareg and Islamist uprising in 2013, but since then jihadists have spread from the north to the center and even targeted Bamako - as in 2015, when gunmen killed 20 people in a raid on a hotel - and Mali’s neighbors.

In June, a suicide bomber drove a vehicle laden with explosives into the headquarters of the regional G5 Sahel anti-terrorist force in Severe, central Mali, killing three people.