GENEVA, May 5 (Xinhua) -- A UN official on Tuesday said that conditions in many prisons in the region of Americas are deeply worrying with thousands of inmates and prison officials being infected by the novel coronavirus.

"Pre-existing structural problems, such as chronic overcrowding and unhygienic conditions, coupled with the lack of proper access to healthcare, have enabled the rapid spread of COVID-19 in many facilities," Rupert Colville, spokesperson for the UN High Commissioner for Human Rights, told a press briefing here.

He welcomed measures taken by some countries to release from prisons those most vulnerable to COVID-19, but said that broader measures are needed to reduce the extreme levels of overcrowding by releasing other categories of prisoners serving short sentences for non-violent crimes, as well as children held in detention and people detained for immigration offences.

In response to a question from the press, Colville said that the United States has a large prison population, and a significant number of COVID-19 cases has been recorded in prisons across the country.

Another problem in the United States is immigration detention, where testing is not enough, he added.