The meeting was called at the Clinton administration's request after the nuclear tests by the two South Asian countries.

A draft statement being considered by the foreign ministers rejects calls for India and Pakistan to be formally admitted to the group of countries with official nuclear weapon status.

The BBC diplomatic correspondent says the big five powers - who are the only countries with that status - want to convince the world that the Nuclear Non-Proliferation Treaty is still valid; and they want to dissuade other countries from joining an arms race that could wreck it.

The statement is also expected to demand that India and Pakistan should refrain from any further action that would raise tensions.

Administration officials say they hope to find ways in Geneva to persuade India and Pakistan to agree a joint statement promising to halt testing and refrain from arming their missiles with nuclear warheads.

The US Secretary of State, Madeleine Albright, is pressing for a concerted strategy to reduce tension between the two countries.

But our correspondent says there is little sign that China, Russia, France and Britain can agree on a common approach with Washington. They already differ on the unilateral American imposition of sanctions.

Ultimately, the United States hopes to persuade India and Pakistan to sign up to the comprehensive test ban treaty, but Mrs Albright stressed that the immediate aim was to lower regional tension by persuading the two countries to avoid inflamatory rhetoric and military provocation.

"Both Indians and Pakistanis are far less secure today than they were three weeks ago," Mrs Albright said.

'Take a deep breath,' says Albright

"Right now, the most important thing both sides can do is to cool it and take a deep breath and to begin to climb out of the hole they have dug themselves into."