Image caption The hunger strike at Guantanamo Bay began in February

The US has reinforced medical staff at Guantanamo Bay to try to handle a spreading hunger strike by prisoners at the detention facility.

About 40 nurses and other specialists arrived at the weekend, camp spokesman Lt Col Samuel House said.

He said that 100 of 166 detainees were now on hunger strike, with 21 of them being force-fed through a tube.

The inmates are protesting against their indefinite detention. Most are being held without charge.

The hunger strike started at the US facility in Cuba in February and has grown rapidly in recent weeks.

Although such actions are frequent at Guantanamo, the current protest is one of the longest and most widespread.

Guantanamo officials deny claims that the strike began after copies of the Koran were mishandled during searches of prisoners' cells.

Violence erupted at the prison on 13 April as the authorities moved inmates out of communal cellblocks where they had covered surveillance cameras and windows.

Some prisoners used "improvised weapons" and were met with "less-than-lethal rounds", camp officials said, but no serious injuries were reported.

Nearly 100 of the detainees have reportedly been cleared for release but remain at the facility because of restrictions imposed by Congress and also concerns of possible mistreatment if they are sent back to their home countries.

The military detention centre opened in 2002 to hold suspects captured in counter-terrorism operations after the 11 September 2001 attacks in the US.