The authoritarian leader of Belarus warned political opponents Thursday that authorities won't allow any unsanctioned demonstrations following the weekend election in which he is seeking a sixth consecutive term.

President Alexander Lukashenko, who has ruled the ex-Soviet nation with an iron hand for 26 years, is facing an upsurge in opposition protests fueled by the worsening economy and the Belarusian government's botched response to the coronavirus pandemic.

Election officials barred Lukashenko's two main challengers from the race, leaving a former English teacher who is the wife of a jailed opposition blogger as the candidate trying to unseat the president. But Sviatlana Tsikhanouskaya, 37, has managed to unite the fragmented opposition in Belarus and drawn tens of thousands to her campaign rallies.

A woman argues with police as they block protesters , to prevent a rally in support opposition candidate Sviatlana Tsikhanouskaya ahead of Sunday's election in Slutsk, Belarus, Tuesday, Aug. 4, 2020. Belarusian police on Tuesday abruptly banned Tsikhanouskaya's previously approved rally in the city of Slutsk, about 100 kilometers (about 60 miles) south of Minsk, under the pretext of road repairs. Officers dispersed several hundred people who had gathered for the rally and detained at least 20 of them, according to Belarusian human rights organization Viasna. (AP PhotoSergei Grits)

A woman argues with police as they block protesters , to prevent a rally in support opposition candidate Sviatlana Tsikhanouskaya ahead of Sunday's election in Slutsk, Belarus, Tuesday, Aug. 4, 2020. Belarusian police on Tuesday abruptly banned Tsikhanouskaya's previously approved rally in the city of Slutsk, about 100 kilometers (about 60 miles) south of Minsk, under the pretext of road repairs. Officers dispersed several hundred people who had gathered for the rally and detained at least 20 of them, according to Belarusian human rights organization Viasna. (AP PhotoSergei Grits)

Police have detained over 1,360 participants in opposition protests since the start of the campaign in May, according to the Viasna human rights center in Belarus.

Looking increasingly nervous in the face of the anti-government protests, Lukashenko, 65, met with his top security officials Thursday and warned against any attempts to stage demonstrations after Sunday's vote. The opposition staged rallies after previous elections to protest the outcome as rigged, and is expected to try to do the same if the president wins again this time.

“God save us from setting up a fire in the center of Minsk,” he said at the meeting. “We can't and will not allow that to happen.”

FILE In this file photo taken on Sunday, Aug. 2, 2020, Sviatlana Tsikhanouskaya, candidate for the presidential elections greets people waving old Belarus flags during a meeting to show her support , in Brest, 326 km (203,7 miles) southwest of Minsk, Belarus.  Tsikhanouskaya, 37-year old former English teacher without any political experience seems an unlikely challenger to the authoritarian leader of Belarus, whose rule has spanned more than quarter-century. (AP PhotoSergei Grits, FILE)

FILE In this file photo taken on Sunday, Aug. 2, 2020, Sviatlana Tsikhanouskaya, candidate for the presidential elections greets people waving old Belarus flags during a meeting to show her support , in Brest, 326 km (203,7 miles) southwest of Minsk, Belarus. Tsikhanouskaya, 37-year old former English teacher without any political experience seems an unlikely challenger to the authoritarian leader of Belarus, whose rule has spanned more than quarter-century. (AP PhotoSergei Grits, FILE)

The Belarusian leader described the protests already held as part of a “hybrid war” waged by antagonists, charging that the West, Ukraine and even his country's main ally, Russia, all could be interested in destabilizing his government.

“A hybrid war is being waged against Belarus, and we should expect nasty tricks from any side,” Lukasenko said.

Last week, Belarusian authorities arrested 33 Russian private security contractors on charges of planning to stage “mass riots” in the country ahead of the presidential election. Investigators have alleged a link between them and Tsikhanouskaya's jailed husband, accusations she has dismissed.

In this photo taken on Sunday, Aug. 2, 2020, Sviatlana Tsikhanouskaya, candidate for the presidential elections, speaks to journalists after a meeting in her support in Brest, 326 km (203,7 miles) southwest of Minsk, Belarus.  Tsikhanouskaya, 37-year old former English teacher without any political experience seems an unlikely challenger to the authoritarian leader of Belarus, whose rule has spanned more than quarter-century but she draws tens of thousands to her campaign rallies. (AP PhotoSergei Grits)

In this photo taken on Sunday, Aug. 2, 2020, Sviatlana Tsikhanouskaya, candidate for the presidential elections, speaks to journalists after a meeting in her support in Brest, 326 km (203,7 miles) southwest of Minsk, Belarus. Tsikhanouskaya, 37-year old former English teacher without any political experience seems an unlikely challenger to the authoritarian leader of Belarus, whose rule has spanned more than quarter-century but she draws tens of thousands to her campaign rallies. (AP PhotoSergei Grits)

Moscow has demanded the contractors' quick release, saying the Russians stayed in Belarus after missing their connecting flight to another country. The Kremlin has been particularly irked by Belarus touting the prospect of handing over some of the contractors to Ukraine, which wants to prosecute them on charges of fighting alongside Russia-backed separatists in the country's east.

Dmitry Medvedev, deputy head of Russia's Security Council, accused the Belarusian leadership of trying to cast Russia as an enemy for electoral purposes and warned Wednesday that the action would have “sad consequences” for bilateral ties.

Lukashenko dismissed Moscow's warning.

Police detain a protester to prevent a rally in support of opposition candidate Sviatlana Tsikhanouskaya ahead of Sunday's election in Slutsk, Belarus, Tuesday, Aug. 4, 2020. Belarusian police on Tuesday, abruptly banned Tsikhanouskaya's previously approved rally in the city of Slutsk, about 100 kilometers (about 60 miles) south of Minsk, under the pretext of road repairs. Officers dispersed several hundred people who had gathered for the rally and detained at least 20 of them, according to Belarusian human rights organization Viasna. (AP PhotoSergei Grits)

Police detain a protester to prevent a rally in support of opposition candidate Sviatlana Tsikhanouskaya ahead of Sunday's election in Slutsk, Belarus, Tuesday, Aug. 4, 2020. Belarusian police on Tuesday, abruptly banned Tsikhanouskaya's previously approved rally in the city of Slutsk, about 100 kilometers (about 60 miles) south of Minsk, under the pretext of road repairs. Officers dispersed several hundred people who had gathered for the rally and detained at least 20 of them, according to Belarusian human rights organization Viasna. (AP PhotoSergei Grits)

“Don't try to scare us with consequences,” he said.

The president on Thursday invited top prosecutors from Russia and Ukraine to visit Belarus to deal with the arrested Russian contractors.

Vladimir Isachenkov in Moscow contributed to this report.