WASHINGTON — Attorney General-nominee Eric Holder Jr. today forcefully broke from the Bush administration's counterterrorism policies, declaring that waterboarding is torture and pledging to prosecute some Guantanamo Bay detainees in U.S. courts.

It was the latest signal that President-elect Barack Obama will chart a new course in combatting terrorism. As recently as last week, Vice President Dick Cheney defended waterboarding, a harsh interrogation tactic that simulates drowning, saying it provided valuable intelligence.

The CIA has used the tactic on at least three terrorism suspects, included alleged Sept. 11 mastermind Khalid Shaikh Mohammed. In past hearings, Attorney General Michael Mukasey and his predecessor, Alberto Gonzales, frustrated senators by repeatedly sidestepping questions about waterboarding.

It was the first topic discussed at Holder's confirmation hearing, and he made an unambiguous statement about its nature: "Waterboarding is torture."

The declaration sent a wave of approval through the public viewing gallery, where protesters, dressed in orange prison scrubs like those worn by detainees at the Guantanamo Bay military prison, held signs calling for an end to torture.

Holder said that shuttering Guantánamo would be difficult and would take time. Many detainees could be transferred to other countries, he said, and some could be charged and jailed in the U.S.

That is a contentious proposal because many oppose the idea of bringing terrorism suspects onto U.S. soil.