The United Nations Human Rights office Friday slammed the life sentences given to eight prominent Shi'ite activists, saying the convictions reflect marks of “political persecution.'

United Nations High Commissioner for Human Rights Navi Pillay is writing Bahrain King Hamad bin Isa al-Khalifa to air her concerns.

A special court in Bahrain on Wednesday sentenced the activists to life in prison on charges of plotting to overthrow the government following opposition protests earlier this year.

A total of 21 people were on trial, and the sentences handed down include a life term for prominent Shi'ite political leader Hassan Mushaima, and a five-year sentence for pro-reform figure Ibrahim Sharif.

The Sunni-ruled nation has arrested hundreds of mostly Shi'ite protesters and put dozens on trial in the special courts. International rights groups have criticized the trials as being politically motivated.

Bahrain's crackdown on the anti-government protesters in March left 24 people dead. Bahrain has insisted is it open to dialogue and has denied reports of human rights abuses.

A government press release issued on Friday quoting spokesman Nawaf Almuawdah said Bahrain's judicial process is fair and transparent. He added that “no country could tolerate armed protesters” seeking a government overthrow.