Hard-core detainees at Guantanamo Bay routinely hurl their waste and vomit at their guards in daily, stomach-turning acts of defiance, a top Pentagon official told lawmakers.

"Splashing," as Marine Gen. John Kelly, the commander of U.S. Southern Command, called the practice in testimony before the Senate Armed Services Committee, is just one of the occupational hazards faced by the men and women guarding some 122 prisoners who remain at the compound. Kelly later elaborated that the term referred to throwing "a little cocktail" of "feces, urine, sperm, vomit" at the guards.

"If they can assault the guards physically, they'll do it."

- Marine Gen. John Kelly

Guards have also been assaulted by prisoners and kneed in the groin, according to Kelly.

"If they can assault the guards physically, they'll do it," he said, vowing "I will not back off" from protecting the guards.

Abusive prisoners are restrained and sometimes moved to single cells, he said.

Kelly also said he was troubled by recent rulings from two military judges restricting female guards from dealing with several prisoners - including 9/11 mastermind Khalid Sheikh Mohammed, who complained that it was against Islam.

"Call me crazy -- that sounds like gender discrimination," Kelly said. "I'm also ashamed that I'm doing it," he said of limiting the duties of female guards."

Word of the disgusting practice of terrorists throwing their bodily fluids at guards first surfaced last year, when Army Col. David Heath, the Guantanamo camp commander, said "splashing" by the prisoners was a near daily occurrence.

"In my experience, in the last four months it happens probably once a day," Heath told Agence France-Presse. "They don't discriminate in splashing. If you are at the right place at the wrong time, they'll splash whoever they can splash."

President Obama has vowed to close Guantanamo Bay, freeing dozens of detainees, including five who were traded for accused deserter Sgt. Bowe Bergdahl. Of those still at the facility, 55 have been cleared for repatriation or release to another country that will accept them, a Pentagon spokesman told Military.com.

Kelly said that the recidivism rate for those released from Guantanamo ranged as high as 30 percent, though the White House and State Department have maintained that the rate was closer to six percent.