He also pledged action against American military prison guards and perhaps others responsible for prisoner abuses in Iraq that have drawn worldwide condemnation.
"People are disappointed in the United States," Powell said. He added, "Justice will be done."
Powell said he has made clear, specifically to Arab leaders, that systematic torture of prisoners is unacceptable anywhere. Yet, he said, their denunciation of the killing of Nicholas Berg, kidnapped while in Iraq seeking business for his Pennsylvania communication company, fell far short of their attacks on the United States for the treatment of detainees at Baghdad's Abu Ghraib prison.
Berg's killers mentioned the prisoner abuse in a taped statement they made just prior to beheading him.
In an interview broadcast Monday, Berg's father said that he holds Secretary of Defense Donald Rumsfeld responsible for his son's death and called for his resignation.
Speaking to Israel Army Radio, Michael Berg said Rumsfeld bears most of the responsibility for his son's death.
"I very definitely do hold the Department of Defense, the FBI, the Bush administration and especially Donald Rumsfeld responsible," Michael Berg said.
"He (Rumsfeld) said he is taking responsibility for the sexual abuse scandal … he hasn't really taken responsibility, he didn't lose his son, he didn't lose anything," Berg told the radio.
The murder of the 26-year-old was broadcast on an Islamic militant Web site. U.S. intelligence officials have concluded that terrorist leader Abu Musab al-Zarqawi was the masked person shown decapitating Berg with a large knife.
Powell, interviewed from Jordan, said he has told Arab leaders, "When you are outraged at what happened at the prison, you should be equally, doubly outraged at what happened to Mr. Berg."
On "Fox News Sunday," Powell said, "That is equal to any other act you've seen with respect to the need to condemn it, and to condemn it outright, and to condemn it publicly. And we need that same level of outrage and condemnation coming from the Arab world, just as it's coming from us."
The Islamic militant groups Hezbollah and Hamas issued strongly worded condemnations of the killing. Saudi Arabia and the United Arab Emirates were the first Arab governments to criticize the murder after an initial silence throughout the region about the videotape.
"Notwithstanding what people think about what we did at the prison, there can be no comparison to the actions of a few who are going to be punished and brought to justice as a result of what happened at Abu Ghraib," Powell told NBC's "Meet the Press."
"There is anger in the Arab world about some of our actions, but that is no excuse for any silence on the part of any Arab leader for this kind of murder," Powell said. "This kind of murder is unacceptable in anyone's religion, in anybody's political system that is a political system based on any kind of understanding and respect for human rights."
Berg's burial and a private memorial were held Friday.
It is hoped the gruesome video of his killing may help find al-Zarqawi, ally of Osama bin Laden.
CBS News Correspondent Cami McCormick in Baghdad says authorities are studying the gruesome videotape of the slaying that appeared on the Internet for any clues to the whereabouts of the wanted terrorist. He's believed to be traveling through Iraq.
Brig. Gen. Mark Kimmitt, the top U.S. military spokesman in Iraq, said it may take a while and Zarqawi may have the ability to evade capture -- but he will be caught eventually.
President Bush focused on the Berg slaying in his weekly radio address Saturday, insisting Berg's killers must be hunted down as part of a strategy ultimately designed to bring peace to the U.S.-occupied country.
"We must confront the enemy and stay on the offensive until these killers are defeated," Mr. Bush said in his weekly radio address, as he sought to shift attention from.