The list includes Burma, China, Iran, Iraq, North Korea and Sudan, but not Saudi Arabia even though that country came under heavy criticism in a preliminary report last October.
The six "countries of particular concern" were the same ones designated by Mr. Powell last year and a written statement said the status of religious freedom has "not significantly improved" in any of them since then.
The State Department is required to report annually on the status of religious freedom in countries around the world under the International Religious Freedom Act approved by Congress in 1998.
Countries cited for especially poor records on freedom of worship can be subject to U.S sanctions, though most of the nations on the list already face various human rights or other penalties and officials here say the administration has not decided whether seek additional punitive measures.
The designation of the six countries of concern was a follow-up to the State Department's annual religious freedom report which was issued last October.
The document was critical of a number of other countries including key Gulf ally Saudi Arabia, and nations strongly supporting the U.S-led war on terrorism, among them Pakistan, Turkmenistan and Uzbekistan.
The report flatly said that religious freedom did not exist in Saudi Arabia, and that the government there barred any public observance of non-Muslim faiths.
The State Department in October left open the prospect that Saudi Arabia might be cited as a serious violator of religious rights, and Wednesday's statement did not explain how Mr. Powell reached his determinations.
One official however denied that the absence of Saudi Arabia from the list was related to the possible U.S-led war with Iraq, and said the Bush administration would strongly press Saudi authorities to ease religious restrictions.
An independent advisory commission on religious freedom, also set up by the 1998 legislation, criticized the State Department in October for not taking tougher actions against China and Sudan for their repression of religious practices.
It also recommended that Saudi Arabia, along with India, Laos, Vietnam, Pakistan and Turkmenistan, be added to the list of "countries of particular concern."
A State Department official expressed hope that the prospect of being added to the list next year will give U.S officials more leverage in trying to persuade those countries to improve their human and religious rights performance.