Secretary of State Colin Powell said Thursday the United States expects to release more detainees from Guantanamo Bay (search) in Cuba soon, but first must make sure that interrogators have learned all they can from them about terrorism activity.

"I expect action on the French detainees in the near future," he said in remarks to high school students in Denmark. But Powell emphasized that many of the detainees would be held indefinitely.

"Some of these are very, very dangerous people who should not be let out," he said.

Powell also told the students at Frederiksberg High School (search) the United States was doing everything it could to counter terrorism and that they should be proud of the contribution being made by Danish troops in Iraq.

About 550 students had gathered in an auditorium to hear Powell.

Ketan Singla, 18, asked why the U.S. administration didn't try "nonviolent policy to solve problems instead of sending troops to war in Iraq."

"No one is more committed to finding diplomatic solutions," Powell answered. "War should be avoided at all costs. [However], when it becomes necessary to use force, one should not shrink to use force."

Finding diplomatic solutions included trying to convince North Korea to abandon its a nuclear program, he said during the 45-minute session.

Kim Boesen, 17, who like the other students quizzed Powell in English, asked whether the U.S.-led war on terror was "a success." Powell responded the war was not over yet. He said in recent years, governments "were getting better and better at getting information on the terrorist networks."

When Powell told the packed auditorium that he had been married to his wife Alma for the past 42 years, students, ages 16 to 20, laughed and applauded.

Powell admitted he "flunked many subjects" when he attended high school, causing laughter.

When leaving the session, two young women who were not students at the school stood up with banners protesting the war in Iraq. Security guards edged Powell out and it was not clear whether he saw the banners.

Danish Defense Minister Svend Aage Jensby (search) resigned last Friday amid criticism that the military had exaggerated the threat posed by deposed Iraqi President Saddam Hussein to justify going to war in the U.S.-led coalition against Iraq.

Referring to his own role leading up to the war, Powell told the students that as a Cabinet officer, he provides "all points of view" and that President Bush "is wise enough and strong enough to listen to all viewpoints."

Powell said discussions leading up to the war were "very informative, occasionally a debate."

Powell's visit to the high school came during a four-hour stop in Denmark during which he met with Queen Margrethe (search), the Scandinavian country's figurehead monarch, and Prime Minister Anders Fogh Rasmussen (search).

Stopping in the Danish capital on his way home from a conference in Berlin about anti-Semitism, Powell became the first secretary of state to visit Denmark since James A. Baker III in 1991.