TALLINN, Estonia (AP) — A Belarusian-American has had his prison term extended to a total of 13 1/2 years in the latest move in a relentless crackdown on dissent by Belarus' repressive government, rights activists said Monday.

Yuras Zyankovich, a lawyer who has dual Belarusian and U.S. citizenship, has been held behind bars since 2021. He was convicted on accusations of plotting to assassinate Belarus' authoritarian President Alexander Lukashenko and seize power and given an 11-year sentence in September 2022. He then had six months added to his sentence later that year.

In August, a court in Belarus handed Zyankovich, 46 an additional two-year sentence on charges of “malicious disobedience to the prison administration,” according to the Viasna human rights group, a ruling that only became known now.

The authorities have denied Zyankovich, 46 access to a lawyer since March.

Zyankovich repeatedly went on hunger strike and his health has seriously deteriorated in custody, according to Viasna, which said that he faced harassment and intimidation by prison authorities.

Last month, Zyankovich featured in a propaganda film aired by state television that described the purported plot he was convicted of.

The U.S. Embassy in Belarus condemned airing the documentary and rejected the “baseless claims” it contained in a statement in September. It emphasized that it will “continue to advocate for the improved welfare of this detained American.”

In 2020, Belarus was rocked by its largest-ever protests following an election that gave Lukashenko a sixth term in office but was condemned by the opposition and the West as fraudulent. According to Viasna, 65,000 people have been arrested since the protests began and hundreds of thousands have fled Belarus.

Belarus has more than 1,300 political prisoners in Belarus, according to Viasna, including the group’s founder and Nobel Peace Prize laureate Ales Bialiatski.