US 'remains committed to European anti-missile defence'

"The United States and European Union have stood side-by-side to prevent Iran from developing nuclear weapons," Mr Biden told the European Parliament. "Iran's nuclear programme violates its obligations under (the nuclear non-proliferation treaty] NPT and risks sparking a nuclear arms race in the Middle East."

The Obama administration last year scrapped Bush-era plans for an expensive missile defence network based in Poland and the Czech Republic. It replaced them with a more flexible plan to deploy Patriot air defence missiles in several countries in eastern Europe and on ships in the Black Sea and Mediterranean.

The original plan strained ties between the United States and Russia, which saw it as directed against its own ballistic missiles. Russia has been more receptive of the new programme, although it still maintains there is no need for it at present.

"Wouldn't it be ironic, as the Iron Curtain fell and the threats of mutual assured destruction diminished among the superpowers, a new arms race would emerge in some of the most unstable parts of the world," Mr Biden said.

Iran denies that it is developing nuclear weapons. It has repeatedly pointed out that the only nuclear-armed nation in the region is Israel, one of America's closest allies.

Mr Biden also urged European politicians to support Nato's combat mission in Afghanistan, which is facing growing opposition in Europe, where many people consider the war unnecessary and unwinnable.