WASHINGTON, June 13 - Vice President Dick Cheney strongly defended the American prison at Guantánamo Bay, Cuba, on Monday, saying that it was essential to the administration's efforts to combat terrorism and that detainees there had been treated better by the United States than they could expect to be treated "by virtually any other government on the face of the earth."

To bolster his remarks, made in a speech at the National Press Club, Mr. Cheney added to the administration's previous warnings about the dangers of moving too quickly to free the more than 500 prisoners held at Guantánamo. He provided new details about what he said had been at least 10 released detainees who later turned up on battlefields to try to kill American troops.

Mr. Cheney mentioned the name of Maulvi Abdul Ghaffar, a released Guantánamo prisoner who returned to Afghanistan and became a Taliban commander and was killed last year by Afghan forces. He also cited Mullah Shehzada, who he said returned from the prison to organize a jail break in Afghanistan, and who was killed last year by American forces.

The vice president's remarks were part of a growing administration campaign to counter increasingly vocal calls on the part of human rights advocates, Democrats and even some Republicans for the closing of the prison at Guantánamo, because of accusations of torture and abuse.