Canada will not join a U.S.-led war on Iraq without a new resolution by the U.N. Security Council, Prime Minister Jean Chretien told the House of Commons today.

Chretien, who received loud applause in Parliament, said: "Canada worked very hard to find a compromise to bridge the gap in the Security Council. Unfortunately, we were not successful. If military action proceeds without a new resolution of the Security Council, Canada will not participate."

While Chretien said that Canada's position has been clear -- that the government would join only a U.N.-sanctioned use of force -- critics have said he had sent conflicting signals over the past weeks.

Last month, Canada asked the United Nations to set an early deadline for Iraq to disarm, and the prime minister called leaders in a number of countries, seeking support for the proposal. Last week, Canada's ambassador to the United Nations delivered a "Canadian compromise" that would have extended the disarmament deadline, but that compromise was rejected by the United States and France.

Canada considers itself among the closest allies of the United States, but according to recent public opinion polls, a majority of Canadians oppose a war without a second U.N. resolution.

Chretien made his statement today after the United States, Britain and Spain, in the face of a veto threat by France, withdrew their call for a U.N. vote to authorize the use of force against Iraq.

Steven Hogue, a spokesman for the prime minister, said Canada had reached its decision "because we feel that it is better for peace to work under the U.N. umbrella."

Hogue made his comments before President Bush's address at 8 p.m., but said that no matter what Bush said, "Canada will not change" its position. Hogue said a small contingent of Canadian soldiers serving in an exchange program with U.S. troops had been authorized to fight alongside them despite the fact that Canada will not join the war. Thirty-five Canadian soldiers are serving with U.S. units in a long-term personnel exchange program. Canadian officials have said it is unlikely the troops will be on the front lines.

Hogue said those officers would remain. "We are not pulling the exchange troops back," Hogue said. "My understanding is they are not on the ground with guns at the border of Iraq. Most likely, they are people sitting at desks, and we are comfortable with that."

Alexa McDonough, foreign policy spokeswoman for the opposition New Democratic Party, said Canada should ask those officers to return home. "Once Bush declares an illegal war on Iraq, the terms of reference will change for those officers," McDonough told reporters. "We should bring them home quickly."

Other members of Canada's opposition also criticized the government, saying they were disappointed Canada would not be standing with the United States. "Canada finds itself frozen on the outside," said Stephen Harper, leader of the Canadian Alliance. "In all the great conflicts of the 20th century, Canada and the U.S. have fought side by side. Frankly, the reality is Canada was often at the forefront of those conflicts. In threats of world security, democracy and freedom, we are disappointed we are no longer a leader."

Canadian Prime Minster Jean Chretien, center, receives a standing ovation in Parliament after declaring Canada would not join a war in Iraq without U.N. approval.