US Secretary of State Condoleezza Rice and Russian Foreign Minister Sergey Lavrov discussed the issue and agreed that both sides would continue talks 'with a view toward early results,' a joint statement said.

The new push came from Presidents George W Bush and Vladimir Putin, who held two days of talks ending Monday at the Bush family estate in Maine.

Both sides want to reduce strategic nuclear arsenals 'to the lowest possible level consistent with their national security requirements and alliance commitments,' the statement said.

The START pact, negotiated by the US and the Soviet Union but formally in force since 1994, limits the United States and Russia to 6,000 deployed nuclear warheads. It also scrapped Soviet-era nuclear arsenals in Kazakhstan, Belarus and Ukraine.

Joseph cited confidence-building and 'transparency,' such as data exchanges and site visits, as issues for the post-START talks.

Meanwhile, Moscow views the effort as 'a continuing process of nuclear reduction,' Russian Deputy Foreign Minister Sergey Kislyak told a joint news conference in Washington.

Separately, Bush and Putin agreed to boost US-Russian cooperation in promoting civilian nuclear power, especially in poorer countries, while avoiding the spread of nuclear materials and weapons.

One part of the effort is for both countries to provide nuclear fuel services, including international nuclear fuel cycle centres that enrich uranium under safeguards of the UN's International Atomic Energy Agency (IAEA), the two leaders said in a joint statement.

'This expansion of nuclear energy should be conducted in a way that strengthens the nuclear nonproliferation regime,' they said.