Six US sailors have been accused of abusing detainees at a prison camp in Iraq, the US navy said.

The sailors are to face military trials over the allegations, which include locking prisoners at Camp Bucca, southern Iraq, in a cell filled with pepper spray, the navy said on Thursday.

Two detainees also were allegedly beaten and suffered minor injuries, said Commander Jane Campbell, a spokesman for the Navy's 5th fleet.

The US military has been damaged by abuse scandals at Abu Ghraib in Iraq and the Guantanamo Bay detention centre in Cuba.

The incidents allegedly took place in May at Camp Bucca, a vast desert camp where the US military houses 18,000 of its 21,000 prisoners in Iraq.

Chemical weapon

The six sailors were charged with assault on detainees and will face courts-martial at Camp Bucca within the next 30 days, the navy said.

"The day that this all took place there had actually been some unrest at the camp. There had been some detainee-on-guard issues, which ranged from spitting to throwing bodily functions at some guards," Campbell said.

The use of pepper spray in warfare is banned by international treaties on chemical weapons, but many governments say their armed forces are permitted to use it in conflict zones for law-enforcement duties.

Seven other sailors received non-judicial punishment for failing to report the incidents, Campbell said.

Two had their charges dismissed while others were reduced in rank or faced suspended punishment, she added, declining to be more specific.