MINSK, BELARUS -- Authorities in Belarus detained a leader of striking factory workers and threatened demonstrators with criminal charges Friday in the latest response to massive post-election protests challenging the country's authoritarian president of 26 years, who accused the United States of fomenting the unrest.

Investigators also summoned several opposition activists for questioning as part of a criminal probe into a council they created with the stated goal of co-ordinating a transition of power with the government and the protesters demanding President Alexander Lukashenko's resignation.

President Alexander Lukashenko blamed the U.S. of instigating the protests that started on the night of the Belarus' Aug. 9 presidential election and intensified after officials declared him the winner with 80% of the vote.

"The U.S. is planning and directing everything, and the Europeans are playing up to it," Lukashenko said while visiting a state farm to rally support Friday.

The United States on Thursday urged Belarus' authorities to engage in a dialogue with the opposition council and described the election that handed Lukashenko a sixth term as neither free nor fair. European Union leaders said this week they were preparing sanctions against Belarusian officials.

Speaking to agricultural workers, Lukashenko bluntly rejected Western offers to mediate between his government and the opposition, telling the U.S. and the EU to mind their own business.

"It's just a convenient way to distract attention from their own problems," he said. "They should sort out their own affairs first."

Belarus' Interior Ministry said Friday that Yevgeny Bokhvalov, who organized the strike at the huge Minsk Automobile Plant, was detained, but gave no further details. Workers at the factory where heavy trucks are made have been on strike since Monday to show solidarity with the election protesters, as have workers at with many other industrial plants across the country.

The strike committee at the giant Belaruskali potash factory in Soligorsk said agents from state intelligence agency KGB detained one of the organizers of the walkout, Dmitry Kudelevich, but he managed to escape through a toilet window and fled to neighbouring Ukraine.

The labour action has presented a tough challenge to 65-year-old Lukashenko, who relied on blue-collar workers as his core support base throughout his iron-fisted rule.

In a bid to halt the strike, the Belarusian leader has warned that the participants would face dismissal and ordered law enforcement agencies to protect factory managers from opposition pressure.

"Most of all, Lukashenko fears the factory workers' protest, so he tries to scare strike organizers and stop the strikes," said Sergei Dylevsky, the leader of the strike-organizing committee at the Minsk Tractor Plant.

Dylevsky, a member of the opposition Coordination Council created set up this week to facilitate the transition of power, was summoned for interrogation along with another council member, lawyer Maxim Znak.

"Even if they arrest us, it will not stop the protests and make Lukashenko look legitimate," Dylevsky said.

Early Friday, police deployed to block the streets around the headquarters of the Investigative Committee where the opposition activists were to be questioned. Several dozen demonstrators rallied nearby to protest the authorities' actions as the post-election protests entered their 13th straight day.

"Hundreds of KGB operatives came to factories to question and scare the workers," said 53-year-old engineer Andrei Yelkin who works at the Minsk Automobile Plant. "We are calling for dialogue, but the authorities are responding with threats and new repressions."

In a bid to stem the daily demonstrations, Belarus Prosecutor General Alexander Konyuk on Friday warned that participants in unsanctioned protests could face criminal charges.

The Prosecutor General's office has opened a criminal probe into the creation of the Coordination Council, charging it violated the constitution and threatened national security. The council members have rejected the accusations and insist their actions fully comply with Belarusian law.

The council has called for a new presidential election organized by newly formed election commissions, as well as for an investigation into the protest crackdown and compensation for victims of police violence.

During the first four days of post-election protests, police detained almost 7,000 people and injured hundreds with rubber bullets, stun grenades and clubs. At least three protesters died.

The crackdown fueled massive outrage and swelled protesters' ranks, forcing authorities to change tactics and stop breaking up crowds. But after standing back for several days, police again beefed up their presence on the streets and deployed outside major factories that have joined the strike.

On Friday, Lukashenko once again derided the opposition as Western puppets and vowed to take steps to quickly end the protests.

"You shouldn't worry about that. It's my problem that I must solve. And believe me, we will solve it in the nearest days," he said. "They mustn't destroy the country, we will not allow that to happen."

Hundreds of state television employees have also gone on strike this week, shaking the government's control of the media. Lukashenko acknowledged Friday that several Russian TV journalists were working at Belarusian state TV to fill the gap.

Seeking to tighten control over information, the state publishing house has stopped printing top independent newspapers, the Narodnaya Volya and Komsomolskaya Pravda, citing equipment malfunction.

"It effectively amounts to the introduction of censorship," said Narodnaya Volya editor Iosif Seredich, adding that the newspaper had been covering the alleged manipulation of the vote results and the police crackdown on protesters.

Sviatlana Tsikhanouskaya, Lukashenko's leading election challenger and the wife of an opposition blogger who has been jailed since May, urged factory workers to continue striking in a video statement released Friday.

"The future of Belarus, the future of our children depends on your unity and resolve," she said.

Tsikhanouskaya, who left Belarus for Lithuania after contesting the election results that gave her 10% of the vote, spoke later Friday at a news conference in Vilnius. She demanded the release of all detained protesters and called for a new presidential election.

Her lawyer on Friday submitted a formal appeal to Belarus' Supreme Court to try to get the Aug. 9 vote invalidated.

"New fair, free and transparent elections must be held," Tsikhanouskaya said. "People of Belarus have woken up, and they do not want to live in fear and lies anymore."

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Vladimir Isachenkov in Moscow and Liudas Dapkus in Vilnius, Lithuania, contributed to this report.