The U.S. decision to go to war in Iraq without the approval of the United Nations Security Council was illegal, UN Secretary General Kofi Annan said in a BBC interview Wednesday.

"From our point of view and the UN Charter point of view, it was illegal," he said. "I hope we do not see another Iraq-type operation for a long time – without UN approval and much broader support from the international community."

Military action is allowed under the UN Charter when approved by the Security Council.

Before the U.S.-led invasion into Iraq, the United States tried to get the UN Security Council to approve the action. But when that appeared unlikely, it said it didn't need approval from the United Nations.

At the time, Annan said an invasion without Security Council approval wouldn't conform to the Charter.

A number of countries that supported the decision of the United States to remove Saddam Hussein from power, including Britain and Australia, disputed Annan's latest assessment.

Annan also said during the BBC interview that the Iraq elections, scheduled for January, are threatened by the continuing violence in the country.

There could not be "credible elections if the security conditions continue as they are now," he said.