Belarusian strongman Alexander Lukashenko on Saturday ordered his defence minister to take "stringent measures" to defend the country's territorial integrity after mass protests erupted against his claim to election victory. 

The 65-year-old authoritarian leader, who said he won a sixth presidential term with 80 percent of the vote in the August 9 ballot, made the comments during an inspection of military units in Grodno, near Belarus's border with Poland, according to the president's press service.

Lukashenko denounced the recent mass protests, which he said were receiving support from Western countries, and ordered the army to defend western Belarus, which he described as "a pearl". "It involves taking the most stringent measures to protect the territorial integrity of our country," Lukashenko said.

His visit comes ahead of large-scale military exercises planned in the Grodno region between August 28 and 31. The former collective farm director said that NATO troops in Poland and Lithuania were "seriously stirring" near their borders with Belarus and ordered his troops into full combat readiness.

Opponents of Europe's longest serving leader have organised strikes and the largest demonstrations in the ex-Soviet country's recent history to protest his re-election and demand that he stand down. The authorities have opened a criminal investigation into the opposition's Coordination Council, whose members are seeking new elections and a peaceful transition of power.

Lukashenko has rejected the idea of holding another ballot, dismissed calls to resign and accused the opposition of attempting to seize power. On Friday he vowed to "solve the problem" of the protest movement.

Lukashenko's election challenger Svetlana Tikhanovskaya, who is now in exile in Lithuania, said this week that Belarusians would "never accept the current leadership again" after the crackdown on post-election protests.