Amnesty International says a prominent activist in the United Arab Emirates has been on hunger strike for over three weeks to protest his prison conditions and conviction.

Ahmed Mansoor is serving a 10-year prison sentence for criticizing the government in social media posts. He was convicted of seeking to damage the UAE's reputation and relationship with neighboring states by posting false reports and information.

An electrical engineer with a master's from the University of Colorado Boulder, Mansoor was the recipient of the prestigious Martin Ennals Award for Human Rights Defenders in 2015.

Amnesty International's Lynn Maalouf said Wednesday that Mansoor has been kept in solitary confinement since his arrest two years ago. She expressed concern that his lengthy hunger strike would result in the deterioration of his health.