L'AQUILA (Italy) - US PRESIDENT Barack Obama will invite leaders from 25-30 countries to a March 2010 global summit on securing nuclear materials and battling atomic smuggling, the White House said on Wednesday.

Mr Obama is hosting the gathering because he 'believes nuclear terrorism is the most immediate and extreme threat to global security,' Mark Lippert, chief of staff of the US National Security Council, told reporters on a conference call.

The summit's key goals will be securing vulnerable stockpiles of nuclear materials from theft and boosting global cooperation to combat the trafficking of atomic materials and know-how, said Mr Lippert.

Mr Obama, in this Italian town for the annual Group of Eight summit, floated the idea on Monday during talks with Russian President Dmitry Medvedev and suggested 'the strong possibility' that Moscow would host a follow-up summit.

'We think this is another important piece of the non-proliferation agenda that the president has put forward,' the US official said, adding that the gathering aimed to broaden Washington's 'robust' bilateral arrangements on that front to a more multi-nation approach.

The summit will seek steps towards securing all vulnerable nuclear materials worldwide within four years, break up black markets in atomic goods, detect and intercept materials in transit, and use financial tools to disrupt illicit trade in nuclear materials, the White House said in a fact sheet.

The hoped-for result would be a joint statement in which the attending world leaders pledge 'the highest levels of nuclear security,' which is key to 'the development and expansion of peaceful nuclear energy worldwide,' it said.

'We should not wait for an act of nuclear terrorism before working together to collectively improve our nuclear security culture, share our best practices and raise our standards for nuclear security,' the White House said. -- AFP