The United Arab Emirates is holding activist Ahmed Mansoor under “abhorrent detention conditions” that violate his rights as a prisoner, according to a new report from Human Rights Watch.

Mansoor, an electrical engineer, poet and human rights defender, was arrested by Emirati security forces in a late-night house raid in 2017. The father of four was later handed a 10-year jail sentence and fine of 1 million dirhams ($272,000) in 2018 for “insulting the status and prestige of the UAE,” a charge connected to social media posts that were critical of the UAE government or called for reform. 

According to the report published Wednesday with the Gulf Centre for Human Rights, Mansoor has been held in an isolation ward of al-Sadr prison, living in solitary confinement in a cell "barely the size of a 2 x 2 meter parking spot" (6.5 x 6.5 foot) without access to reading materials, a mattress or other basic necessities. Since his arrest, Mansoor’s been denied regular visits or calls from his wife and four sons, the report said. 

Human Rights Watch said its findings came from interviews with two former prisoners, as well as a source with “direct knowledge” of Mansoor’s legal proceedings.