FACTBOX: What is waterboarding?

(Reuters) - U.S. Attorney General Eric Holder ruled out the use of "waterboarding" on terrorism suspects on Monday, calling the interrogation technique a form of torture that the Obama administration could never condone.

Following are several facts about the controversial tactic, which human rights advocates also condemn as torture:

* Former U.S. President George W. Bush authorized the CIA to use waterboarding during interrogations of senior al Qaeda suspects after the September 11 attacks in 2001. Bush insisted that the United States does not torture.

* Then-CIA Director Michael Hayden told Congress last year that waterboarding was used against the alleged planner of the September 11 attacks, Khalid Sheik Mohammed, and two others -- senior al Qaeda members Abu Zubaydah and Abd al-Rahim al-Nashiri. Hayden also told lawmakers he was not certain the technique would be legal under current U.S. law.

* According to Human Rights Watch, waterboarding dates at least to the Spanish Inquisition. In some versions, the group says prisoners are strapped to a board, their faces covered with cloth or cellophane, and water is poured over their mouths to simulate drowning. In other versions, prisoners are dunked headfirst into water.

* The technique causes reflexive choking, gagging and the feeling of suffocation.

* Waterboarding was used in Central and South America in the 1970s and 1980s, the rights organization says.

(Reporting by David Morgan in Washington; editing by John O'Callaghan)