Prison guards at Guantanamo Bay clashed with detained terrorist suspects on Saturday, U.S. military officials said, leading to shots being fired.

{mosads}The commander of Joint Task Force Guantanamo ordered the transfer of detainees from “communal to single-cell living” at Camp 6 “to ensure the health and security of those detainees,” according to a statement.

The transfer was ordered after detainees covered surveillance cameras, windows and glass partitions, restricting the guards’ ability to observe them.

Some detainees, however, resisted the move, and guards fired shots.

“Some detainees resisted with improvised weapons, and in response, four less-than-lethal rounds were fired. There were no serious injuries to guards or detainees,” the military said its statement.

Detainees were also given medical check-ups due to an ongoing hunger strike, according to the military.

Last week, the top human rights official at the United Nations said that the U.S. prison at Guantanamo Bay was in “clear breach” of international law and should be closed.

U.N. High Commissioner for Human Rights Navi Pillay said she was “deeply disappointed” that the Obama administration had yet to close it.

One of President Obama’s first moves in office was an executive order that called for closing the prison in Cuba, but he gained little traction to do so during his first term, due in part to congressional opposition.