MINSK, BELARUS (NYTIMES) - He bungled the coronavirus pandemic, alienated his longstanding foreign ally and last week faced the biggest anti-government protests in decades, but on Sunday (Aug 9), President Alexander Lukashenko of Belarus was on course to win his sixth term in office, in an election his critics dismissed as rigged.

According to a government-sponsored exit poll released after voting ended, Mr Lukashenko won just under 80 per cent of the vote against four rivals, avoiding a runoff.

A heavy cloak of security descended over the capital, Minsk, where Internet service was cut off, phones worked only sporadically and soldiers and riot police cordoned off the central square and the main public buildings.

Long before the results were announced, the opposition, predicting that the count would be illegitimate, had called for protests on Sunday night.

Tension escalated sharply on Sunday evening after a police truck rammed into a crowd of protesters blocking a major avenue in the centre of the capital, injuring several people.

Skirmishes also broke out in other parts of the city between opposition supporters and security forces.

The downtown area vibrated with the din of stun grenades as security forces, backed by water cannons, moved in to break up crowds of opposition supporters who gathered throughout the evening in locations across the city.

The result of the vote, as in previous elections, was never in any real doubt: Mr Lukashenko controls vote counting, a vast security apparatus and a noisy state media machine unwavering in its support for him and contempt for his rivals.

Facing the biggest outpouring of dissent during his 26 years of autocratic rule, he hoped to return his restive country to the predictable political rhythms that have kept him in power.

"Nothing will get out of control. This I guarantee," Mr Lukashenko said on Sunday, warning that anyone seeking to upset stability "will receive an immediate response from me".

Security services arrested hundreds of protesters and many journalists in recent days, and on the eve of voting, the principal challenger, Ms Svetlana Tikhanovskaya, went into hiding in Minsk after security agents detained at least eight members of her campaign staff.

The exit poll showed her in second place, with less than 7 per cent of the vote.

Thousands of opposition supporters also gathered on Sunday night near a war museum in Minsk to contest the apparent election results, and security officers detained dozens of them.

Protesters blocked a nearby avenue, with police officers firing stun grenades in an effort to dislodge them.

Ms Tikhanovskaya had entered the race after her husband, Sergey Tikhanovsky, a popular blogger and would-be presidential candidate, was arrested and thrown in jail on what were widely viewed as trumped-up financial charges.

Mr Lukashenko, unfazed by criticism of widespread pre-election repression, radiated confidence as he cast his vote at a university in Minsk on Sunday morning.

"They aren't even worth repressing," he said of his opponents.

"To be honest, we have been soft so far. I can tell you honestly, we have always restrained the law enforcement."

The opposition, energised by weeks of protests but unable to break Mr Lukashenko's tight grip on the electoral system, dismissed the election as blatantly rigged.

Despite the foregone nature of the election outcome, Mr Lukashenko had been challenged like never before this year, amid the biggest surge of public discontent since he won the presidency for a first time in 1994, the last election in Belarus that outside observers judged to be reasonably free and fair.

He has struggled with a faltering economy, anger over his handling of the coronavirus pandemic, which he denied posed any threat to health, defections by members of the country's economic and political elite and an open rift with his long-time ally and benefactor, President Vladimir Putin of Russia.

A former collective farm manager, Mr Lukashenko enjoyed genuine support at the start of his rule, appealing to voters by preserving many aspects of the Soviet-era economy, including a large but inefficient state-owned industrial sector.

This allowed Belarus, a country of about 9.5 million people, to avoid the chaos endured by former Soviet states like Russia and Ukraine in the 1990s, when a few, aided by cronyism and corruption, built vast fortunes, and millions of others were plunged into poverty.

But his policies have grown increasingly unpopular as the Belarusian economy failed to grow and modernise.

Mr Valery Tsepkalo, the architect of the country's only significant economic success, a high-tech development zone in Minsk, broke with Mr Lukashenko and had planned to run against him in Sunday's election. But Mr Tsepkalo, warned that he, too, would soon be arrested, fled to Russia last month.

With Russia increasingly reluctant to bankroll Belarus through cut-price oil deals, the economy has gone into steep decline and with it Mr Lukashenko's popularity.

His already souring relations with Moscow took a bizarre new turn for the worse last week when his security services arrested 33 Russians, accusing them of being part of a team of mercenaries sent to Belarus to disrupt the election.

A few days later, the authorities also took a swipe at the United States, saying that several suspicious Americans had been arrested, too.

For outside observers, there was little question about the election's legitimacy.

More than 41 per cent of voters cast their ballots before Sunday.

The only international observers in the country were from Russia, Azerbaijan and a few other countries with questionable democratic records.

Ms Tikhanovskaya, who was declared the united opposition candidate in July after Mr Lukashenko's other strong opponents were either arrested or forced to flee, fled her apartment in Minsk on Saturday evening and went into hiding but emerged briefly on Sunday to vote.

She feared arrest, her campaign said, after plainclothes security officers appeared near her apartment building and a riot police van parked nearby.

Many journalists were denied accreditation to cover the elections.

On Sunday, a reporter and cameraman from TV Rain, an independent Russian television station, were arrested in central Minsk.

Three other journalists from the Current Time news outlet, which is affiliated with Radio Free Europe, were detained last Friday and expelled from the country.