Brussels: The US military faces serious budget cuts and will be unable to make up for any shortfalls in the NATO alliance as European members slash defence spending, Pentagon chief Leon Panetta warned on Wednesday.

Fiscal pressures are bearing down on both sides of the Atlantic and NATO allies will need to work closely together to pool funds, instead of counting on America's much larger defence spending to close the gap, Panetta said.

"As for the United States, many might assume that the US defence budget is so large it can absorb the shocks and cover alliance shortcomings -- but make no mistake, we are facing dramatic cuts with real implications for alliance capability," the US defence secretary said in a speech in Brussels.

Although US defence spending far exceeds European budgets, Panetta said American military leaders were facing USD 450 billion in cuts over 10 years, which he called "tough but manageable," according to a prepared text of the speech.

But if the US Congress fails to tackle the country's deficit this year, the Pentagon "could face additional cuts in defence that would be devastating to our national security and to yours as well," he said.

Panetta delivered his warning ahead of talks with NATO counterparts in Brussels, centred on the missions in Libya and Afghanistan as well as the shortcomings the alliance has witnessed in carrying out the operations.

The cuts contemplated by the Pentagon would reduce the size of the force and curtail some weapons programmes, but the gargantuan US defence budget -- at nearly USD 700 billion -- still dwarfs that of the 27 other NATO