The Joint Task Force in charge of the facility said so far the men had refused nine meals over three days and are being monitored by medical professions.

"Indications are that this is a temporary effort by some detainees to protest their continued detention," a spokesman said. "They continue to be offered food and water."

The statement contrasts with accounts offered by two Afghan detainees released this week. They said some 180 terror suspects had been on hunger strike for around two weeks.

The New York-based Centre for Constitutional Rights said lawyers representing the detainees received word of the strike from prisoners.

They said it reflected their peaceful demand to be treated as human beings.

"The vast majority of prisoners live in appalling conditions... and every prisoner is suffering from the effects of indefinite detention without legal process," the group said in a statement.

Barbara Olshansky, deputy legal director, said the strike should signal to the Bush administration that it is about time they were given access to the US legal system.

She added: "We are now hearing not from human rights organisations, attorneys, or the government but from the prisoners themselves that there are real and continued violations of human rights taking place at Guantanamo."

There are around 520 prisoners being held at Guantanamo. Most are Afghans, Pakistanis and others captured after the US invasion of Afghanistan in 2001