Thousands of Belarusians living in Poland joined the protests denouncing the disputed election that resulted in President Alexander Lukashenko being elected for a sixth term.
One protest organiser said they were urging the Belarusian embassy in Warsaw to denounce Lukashenko.
"We submitted a letter to the employees of the Embassy, to the diplomats, asking them to take the side of the nation, to take a side of the real president Svetlana Tikhanovskaya," Anatol Michnaviec said.
Opposition leader Svetlana Tikhanovskaya fled to Lithuania last week, after she said President Lukashenko's government had falsified the election result.
U.S. Secretary of State Mike Pompeo was also in Warsaw on Saturday where he was to meet Poland's prime minister, in part to discuss Belarus.
On Friday Poland's deputy foreign minister said the government was preparing for an influx of people leaving Belarus.
The government has announced an €11 million fund to help protesters secure visas and settle in Poland.
Around 6,700 protesters have been detained by the security services in Belarus. After being released some said they were tortured in prison and displayed extensive bruise marks on their bodies to the media in Minsk.
Stepan Svetlov, who runs online news platform Nexta, managed to evade the government-imposed news blackout but he has been threatened with prosecution.
"Except us, there are almost no other sources of information. Today, I have received information that they opened a criminal case and that I may face a minimum of 15 years, up to 15 years, in prison only because we have been simply delivering information," he told Euronews.
One protester has begun a hunger strike in front of the European Commission building in Warsaw.
"I want the European Union to urgently adopt and introduce sanctions against Lukashenko's regime. That is why I decided to go on hunger strike," Maksim Cherniavski said.
One Polish MP who has just returned from Belarus tried to reassure the protesters gathered outside the European Commission building in on Saturday that he was on their side.
"The Polish parliament is with you. We are here, in front of the building of the Representation of the EC, to appeal to free all the people arrested in these last days and nights," Michal Szczerba told them.