Allegations by Belarusian President Alexander Lukashenko that "foreign powers" are organising a build-up of troops on the country's border are baseless, says Nato. Dressed in military fatigues, the president said he had placed his armed forces on "high alert". Protests continued in the streets of the capital Minsk on Saturday following a disputed election two weeks ago. Demonstrators are demanding that Mr Lukashenko stand down. The leader, who has ruled Belarus for 26 years, accused Nato of trying to split up Belarus and install a new president in Minsk. He said troops in Poland and Lithuania were readying themselves, and that he was moving his armed forces to the country's western border. "They are rocking the situation inside our country, trying to topple the authorities," Mr Lukashenko said, adding that he had ordered his security chiefs to "take the toughest measures to defend the territorial integrity of our country". Nato said it posed "no threat to Belarus or any other country" and had "no military build-up in the region". "Our posture is strictly defensive," it said. "The regime is trying to divert attention from Belarus's internal problems at any cost with totally baseless statements about imaginary external threats," Lithuanian President Gitanas Nauseda told AFP news agency. A Polish presidency official called the suggestion that Poland planned any border destabilisation "regime propaganda" by the Belarusians, which was "sad and surprising". "Poland... has no such intention," the official added. Nato urged Belarus to respect the fundamental human rights of its citizens. Mr Lukashenko was re-elected president on 9 August but the vote was widely considered to be fraudulent. Protests disputing the result were met with a brutal crackdown that killed at least four people and demonstrators said they had been tortured in prisons and detention centres. Large numbers of demonstrators are expected to rally in Minsk again on Sunday. The president has vowed to crush the unrest and has previously blamed the dissent on unnamed "foreign-backed revolutionaries". With protests and strike action continuing, including the walking out of state TV staff, Mr Lukashenko said he had flown in Russian broadcast journalists as cover to "stabilise" the situation, the Belarus state news agency Belta reports. "I've asked Russians to lend us two to three groups of reporters just in case. Six to nine people from the most advanced television company," he said. On Saturday, crowds of protestors waved bright lights from mobile phones and flew Belarusian flags in the streets of Minsk while chanting "freedom".