British Prime Minister Boris Johnson met Tuesday with the Belarusian opposition leader at his office in London, saying the U.K. is "on her side" and committed to supporting human rights in her country.

Johnson told Sviatlana Tsikhanouskaya that Britain is "very much in support of what you are doing" during their meeting at Downing Street, and condemned Belarus leader Alexander Lukashenko's "severe human rights violations and persecution of pro-democracy figures," his office said.

The talks came as international attention focused on Belarus after Olympic sprinter Krystsina Tsimanouskaya refused her team's orders to fly home and took refuge in the Polish embassy in Tokyo. In addition, a Belarusian activist who ran a group in Ukraine helping Belarusians flee persecution was found dead in the Ukrainian capital, Kyiv, local police said Tuesday. An investigation was launched after Vitaly Shishov was found hanged in a city park not far from his home.

"It is very important to understand that one of the most powerful countries in the world is supporting Belarus," Tsikhanouskaya said after meeting with Johnson.

Tsikhanouskaya also met U.S. President Joe Biden last week as part of a tour to move Belarus up the agenda for Western countries. She challenged Lukashenko in the country's presidential election last year but fled Belarus after the long-time leader was awarded a sixth term in office due to a vote that opposition leaders and the West called rigged.

Ahead of her visit to Downing Street, Belarusians living in the U.K. and human rights activists demonstrated in London to highlight criticism of Lukashenko's rule.

"We're trying to show the British government that more needs to be done. We cannot leave Lukashenko to do what he is doing to the country," said Ken McBain, a U.K. representative of the human rights group Libereco.

Tsikhanouskaya told reporters it was too early to comment on the death of Belarusian activist Shishov. But she added: "I understand, you know, I can disappear at any moment. I understand this, but I should do what I am doing."