Belarus on Wednesday freed several political prisoners, exiled opposition leader Svetlana Tikhanovskaya said, a day after President Alexander Lukashenko said he may offer an amnesty to some political detainees with serious illnesses.

Lukashenko, who will mark 30 years as president later this month, has locked up hundreds of political opponents, activists and journalists throughout his rule, while thousands more have fled abroad.

"Today we witnessed the first cases of some political prisoners being released in Belarus," Tikhanovskaya said in a post on X, without saying how many or who had been released.

"I am glad to see these people free and reunited with their loved ones," she added, but said "many" were still behind bars.

The human rights watchdog Viasna estimates Belarus has more than 1,400 political prisoners, including its founder, Nobel Peace Prize winner Ales Bialiatski.

Lukashenko escalated a crackdown after unprecedented protests swept the country when he claimed victory in a 2020 election slammed by rights groups as fraudulent.

There was no official statement from Minsk or reports on state media of the releases on Wednesday.

Lukashenko had on Tuesday told reporters "not to be surprised if in a few days" some "seriously ill" people arrested over the 2020 protests were released.

"They are really seriously ill, mostly with cancer," the Belta state news agency quoted him as saying.

Tikhanovskaya's husband, Sergei Tikhanovsky, is among those jailed in Belarus.

He was not expected to be among those released.

Tikhanovskaya stood against Lukashenko in the 2020 presidential election after her husband's candidacy was barred.

She claimed to have won the vote and fled to EU member Lithuania, from where she has continued to campaign against Lukashenko, including over his support for Russian President Vladimir Putin's invasion of Ukraine.