NATO delivered another setback to the United States Wednesday as four allies again blocked plans for the alliance to send planes and missiles to defend Turkey if there is war with Iraq.

Officials said the U.S. proposals to start preparations to support Turkey in the event of a war in neighboring Iraq were not even discussed at a meeting of the alliance's policy-making North Atlantic Council, after the 19 allies failed to agree in private talks Tuesday.

France, Germany, Belgium and Luxembourg say they do not oppose the U.S. proposals as such. But they feel it is too early to start the military planning while there is still hope of avoiding a war through diplomacy and the U.N. weapons inspections process.

The American proposals include sending AWACS surveillance planes and Patriot missiles systems to Turkey, intensifying naval patrols in the Mediterranean, filling in for European-based U.S. troops sent to the Gulf and an eventual role for NATO in humanitarian or peacekeeping operations in a postwar Iraq.

The decision was first blocked last week. Officials at NATO headquarters said it now could come after Feb. 5, when U.S. Secretary of State Colin Powell is scheduled to present the U.N. Security Council with intelligence about Iraqi weapons programs and alleged links to terrorist groups.

Although NATO Secretary General Lord Robertson insisted this week there was "no bust up" over the issue, diplomats said the debate was becoming tense.

On Monday, Robertson said the alliance must consider the request for "prudent, deterrent and defensive measures" to be ready to help Turkey.

"If you have a neighbor like Saddam Hussein, you're wise to get involved in at least prudent defensive measures for your own safety, and as member of an alliance it has a right to ask for and expect support," Robertson told reporters at the World Economic Forum in Davos, Switzerland.

U.S. officials said they had been hoping for movement after Monday's report by the U.N. weapons inspectors, which was sharply critical of Iraq for failing to offer full cooperation.

However reaction to the report underscored differences among the allies, with Britain and the United States stressing Iraqi leader Saddam Hussein's failure to comply, while Germany and France took up the call for the inspectors to be given more time.

The dispute is raising doubts about NATO's role just two months after alliance leaders at a summit in Prague, Czech Republic, proclaimed the Cold War alliance was reinventing itself to tackle modern threats from terrorism and rogue states.

"NATO is on the sidelines and that's no surprise," said Sir Timothy Garden, of London's Royal Institute of International Affairs.

Garden said NATO's military role was decreasing as the United States increasingly looked to build tailor-made coalitions for conflicts rather than rely on NATO, where all decisions need unanimous support among the 19 members.