MUNICH, Germany (Reuters) - Deep U.S.-European divisions over Iraq have been laid bare as U.S. officials said European reticence over war was harming transatlantic ties, while Germany insisted peace should be given a chance.

U.S. Secretary Donald Rumsfeld told an annual security conference in Munich on Saturday that 12 years of diplomacy, economic sanctions and limited military strikes had failed to disarm Iraq and the world would know in "days or weeks" if war was needed.

He branded as "inexcusable" moves by France, Germany and Belgium to stall NATO planning for the protection of Turkey in the event of a war in Iraq, saying they were undermining NATO's credibility and illustrating deep divisions within Europe.

German Foreign Minister Joschka Fischer told the conference Berlin stood by its obligations to its NATO partners but defended not wanting to push forward planning on Turkey, saying he was still not persuaded of the need for war with Iraq.

"I am not convinced. That is my problem. I cannot go to the public and say these are the reasons because I don't believe in them," he said, switching briefly from German into English.

Waving banners displaying anti-war slogans and blowing whistles, about 6,000 protesters took to the streets of Munich amid heavy snowfall on Saturday to demonstrate against the conference and the threat of military action against Iraq.

Fischer said Germany agreed that the end of the Cold War had disturbed the balance of power in the Middle East but said Islamic extremists and not Iraq posed the main threat and bringing peace to Israel should be the first priority.

He also questioned whether the U.S. public was ready for the long-term occupation that would be needed after an Iraq war.

A speech to the conference by Russian Defence Minister Sergei Ivanov made no mention of Iraq, focusing instead on security threats in Chechnya and Central Asia and arguing they were an integral part of global concern over Islamic extremists.

MOMENTUM BUILDING

Rumsfeld said many in Europe had failed to see the danger of new security threats thrown up by the end of the Cold War and said Washington's main concern was states like Iraq acquiring weapons of mass destruction and passing them onto terrorists.

He said Washington hoped to avoid military action, but a growing number of nations were serious about eliminating Iraq's alleged nuclear, chemical and biological arms but would only succeed if the world was united and determined to use force.

Rumsfeld said it would be clear in "days or weeks we're going to know whether they are going to cooperate".

Baghdad has denied repeatedly that it has such weapons.

"No one wants war. War is never a first or an easy choice. But the risks of war need to be balanced against the risks of doing nothing while Iraq pursues weapons of mass destruction," he said.

"Clearly, momentum is building, momentum that sends a critically important message to the Iraqi regime -- about our seriousness of purpose and the world's determination that Iraq disarm."

Rumsfeld said if a three-week deadlock at NATO over starting planning for the protection of Turkey is not ended, Washington and other allies will provide defence for Turkey anyway, and NATO's credibility would suffer a severe blow.

"What will be hurt will be NATO, not Turkey," he said. "To prevent defensive capabilities -- just the planning, not even deployment -- I think that is inexcusable."

U.S. Senator John McCain was even more forthright, saying France and Germany had dealt a "terrible injury" to the alliance and had undermined efforts to disarm Baghdad peacefully.

"Recent actions by Paris and Berlin have...raised serious doubts among nations on both sides of the Atlantic about their commitment to multinational diplomacy," he told the conference.

Some diplomats say France and Germany have been so angered by disparaging comments by Rumsfeld and other influential U.S. officials, and so strongly backed by public opinion, that they might well stick to their blocking of a NATO decision.

Rumsfeld sought to play down his recent comment that France and Germany's reticence over war had sidelined them, branding them "old Europe", saying at his age "old" was a term of endearment. But he urged Berlin and Paris to get on board:

"As the old saying goes, if you're in a hole, stop digging."

Rumsfeld was to meet defence ministers from Russia, Germany and other countries in Munich before returning to Washington.