(ANSA-AFP) - MINSK, 31 JUL - Tens of thousands of supporters of President Alexander Lukashenko's top election rival on Thursday rallied in the Belarusian capital Minsk despite an increasing crackdown on the opposition. The rally came as Belarus authorities accused top members of the opposition of collaborating with Russian fighters to destabilise the ex-Soviet country. Backers of political novice Svetlana Tikhanovskaya, a stay-at-home mother-of-two, packed a Minsk square in what appeared to be the largest opposition protest in the ex-Soviet country in a decade, an AFP journalist said. A sea of people waved flags and ballons emblazoned with the opposition's campaign symbols -- a victory sign, a clenched fist, and a heart. "Change!" read one of the placards. The human rights organisation Vyasna said at least 63,000 people had turned out. Earlier Thursday, Belarus investigators accused Tikhanovskaya's husband, blogger, Sergei Tikhanovsky, and another prominent critic, Mikola Statkevich, of working together with Russian mercenaries to plot mass unrest ahead of the August 9 election. Both Tikhanovsky and Statkevich were jailed in the run-up to the polls. (ANSA-AFP). (ANSA).