Admiral Guido Venturoni, chairman of Nato's military committee, also refused to contradict widespread suspicions that the air campaign left untouched much of Serbia's heavy artillery and tanks inside Kosovo.
In the most frank formal assessment of the frailties of the alliance's military campaign the admiral hinted that the bombardment of Belgrade and devastation of infrastructure in Serbia may have been crucial in determining the outcome of the air campaign. By inference, at least, the relentless bombardment of Serb forces in Kosovo was less successful.
The admiral, who took over during the air campaign, used a press conference yesterday to plead for a fundamental rethink of the alliance's capabilities and strategy, pointing out that the alliance "had to deploy virtually all of its immediate and rapid reaction forces".
He argued: "The Kosovo crisis demonstrated quite clearly that the alliance needs sufficient modern mission-effective forces with the necessary readiness and availability.
"This is an urgent requirement since, while we did our best this time - such as pre-deployments into the Former Yugoslav Republic of Macedonia - we were surprisingly close to our limit."
Among the failures of intelligence which emerged yesterday was an underestimate of the number of Serb army and paramilitary forces inside Kosovo, put at around 40,000. Yesterday the admiral said a further 7,000 were now thought to have been deployed.
He also declined to confirm Nato's early estimates that well in excess of one-third of Serbia's heavy armour was struck by the alliance. A team of 20 Nato officials will begin a formal inquest this month with a visit to Kosovo which will collect "all possible information which will be analysed and assessed".
With mounting evidence that the Serb forces used decoys and dummies to deceive Nato pilots, statistics on the destruction of tanks have been hard to substantiate. Nato says that the Serbs requested permission to withdraw from Kosovo only 13 tanks which had been damaged.
But Nato also believes that, by demonstrating its ability to disrupt electricity supplies in Belgrade through its use of "soft bombs", it struck a crucial blow against the will of Slobodan Milosevic to resist.