"We agreed on the funds for the destruction of nuclear, bacterial and chemical armaments in the Russian Federation and other countries that used to belong to the Soviet Union," Berlusconi said on the first of a two-day G8 meeting.

The G8 is made up of the United States, Russia, Canada, France, Germany, Britain, Italy and Japan.

"The question of arsenals that could fall into the hands of evil-minded states interests all mankind and the decision (on the fund) was agreed by everyone almost without debate," Berlusconi told a news conference.

Washington, which has already committed around $1 billion next year under existing programmes to help Russia destroy the vast former Soviet nuclear stockpiles, has promoted the new programme in the wake of the September 11 attacks.

Diplomats say Western military chiefs are worried that leaky security at Russian atomic sites makes then vulnerable to al Qaeda and other militant organisations.

Berlusconi said Russian President Vladimir Putin was delighted with the deal. "He was very, very satisfied because we will begin with the arsenals in the Russian Federation," Berlusconi said.

He added that Germany had promised to sink 1.5 billion euros into the fund, while the European Union would provide a further one billion euros. He said Italy would also contribute but did not specify how much cash it would hand over.

Japanese Prime Minister Junichiro Koizumi pledged his country would spend $200 million for the time being, a Japanese official said.

Koizumi noted that Russia was mainly responsible for a delay in the programme, and said Japan would make its contribution on the condition that Russia would proceed with the project, the official said.

Full details of the plan have yet to be worked out but it is especially designed to help Moscow deal with the 30,000 nuclear weapons and the highly enriched uranium and plutonium stocks it inherited when the Soviet Union broke apart in 1991.

Last year, a bipartisan U.S. task force said the need to secure Russian nuclear weapons, materials and scientific knowledge was "the most urgent unmet national security threat to the United States".

The United States and Russia last month signed a treaty under which the two nations agreed to cut their nuclear warheads by the year 2012 to between 1,700 and 2,200 from current levels of around 6,000.