"There is a debate and there is no consensus yet," said an official of the Alliance: "There is a very clear view around the table to start the mission as soon as possible but you have to get it right."

Diplomats said earlier Wednesday NATO was struggling to agree on how exactly it will fulfil its pledge on training Iraqi security forces, with France in particular blocking consensus.

The official said after the late Wednesday session of NATO ambassadors: "There are issues that still need to be discussed and clarified relating to the arrangements of the training mission."

"There are still many issues to be sorted out," said a NATO diplomat, after the fruitless two-hour evening session. The envoys had already convened for two sessions earlier in the day.

Diplomats said the sticking point is whether the training mission will involve a visible NATO presence on the ground in Iraq, as sought by the US administration.

The North Atlantic Treaty Organization (NATO) leaders agreed at a summit in Istanbul last month to provide such training, but left details to be hammered out. France opposes Alliance training inside Iraq.

"Allies want to reach a consensus on this. Most allies want to do it this week... for a training mission inside Iraq beginning as early as next week," said one diplomat earlier Wednesday.

"Over 20 allies support this. Two or three were undecided at the beginning of the week, and it was France who is just saying 'no' and by saying 'no' is blocking consensus," he added.

Another diplomat confirmed that the United States, which has long pushed for a bigger NATO role in Iraq where American troops have been struggling to contain mounting violence, was pushing hard for an accord.

Further ambassador-level meetings could be called later in the week if necessary, NATO officials say.

A NATO military delegation led by US admiral Gregory Johnson was dispatched to Iraq at the start of July to study options for the mission. Diplomats said a second military mission could be sent to Iraq to clarify options.

NATO Secretary General Jaap de Hoop Scheffer said on Monday that he hoped for an agreement by the end of this week on a training mission, both inside and outside Iraq.

This month Iraq's interim Foreign Minister Hoshyar Zebari, part of the Iraqi administration which took over in June, urged NATO to make good quickly on its promise to train security forces.

Zebari said authorities were "in a race against the clock" in their effort to ensure stability.

Crime has soared in Iraq following the US-led invasion with convicts released by Saddam roaming free, creating deep insecurity as crooks seize Iraqis citizens for ransom and extremist networks behead foreign hostages for political reasons.

Another NATO official denied earlier Wednesday that the differences were in any way comparable to the splits which shook NATO to its foundations in the run-up to last year's US-led war against Iraq.

On that occasion France, Germany and Belgium effectively paralyzed the Alliance -- which requires unanimity for all decisions -- by refusing to allow NATO to come to Turkey's aid.

"NATO is very keen to finalize this package... but don't look for repetitions. History does not repeat itself," the official said.

"There is full determination to provide a package as soon as possible on training in and outside of Iraq," he added.

The US ambassador to NATO Nicholas Burns echoed de Hoop Scheffer's aims earlier this week.

"I agree wholeheartedly with the ... (secretary general) that the alliance should decide this week to establish a NATO training mission in Iraq," he told reporters.

"That is what our leaders decided in Istanbul ... NATO needs to act quickly to give the Iraqi government and people the support they so desperately need," he added.

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