Rice seeks UK support over Iran
US Secretary of State Condoleezza Rice is due to meet Tony Blair at Chequers on Sunday for talks over Iran.
They are expected to discuss Iran's nuclear programme and how they hope to prevent it developing nuclear weapons - which it denies wanting to do. READ MORE
Ms Rice's visit is part of a European tour to gather support for encouraging Iran to return to international talks.
Ms Rice also told the BBC Iran should end support of the insurgency in Iraq, and become "good neighbours" instead.
Insurgency 'can't survive'
She said the insurgents trying to derail the process would fail.
"The insurgency can't ultimately survive without a political base," she said.
However, she declined to say how soon she thought the insurgency would last, but added that it was fair to ask the British and American people to support the Iraqis "so that we can finish this job".
Britain believes that Iran is backing the insurgency in Iraq with technical help.
Ms Rice, who arrived in London on Saturday, said: "I have reason to believe that the British are right about this.
"I trust the British on this issue because the British are operating in the south, they know the situation."
She said the Iranians needed to stop such support and become "good neighbours" to the Iraqis.
But the Iranian ambassador in London has insisted his country does not support the use of violence against British troops in Iraq.
Dr Seyed Mohammed Hossein Adeli denied accusations that Iran supplied equipment that led to the deaths of British soldiers.
He also denied his country was causing trouble in Iraq as a response to criticism of its nuclear programme.
He told the BBC Britain and Iran had talked about the attacks through diplomatic channels, and he was suspicious that Britain was highlighting its complaints to put pressure on Iran.
He rejected Washington's belief that Iran wanted to develop nuclear weapons, and said it needed nuclear energy to replace oil stocks when they ran out.
'Right to enrich'
With voting on Iraq's constitution on Saturday, Ms Rice welcomed the referendum exercise as evidence the country was moving towards a democratic future.
he said the country could emerge as a "centrepiece for a different kind of Middle East".
Asked if she took responsibility, as a key architect of the war, for the deaths of thousands of Iraqis as well as nearly 2,000 American personnel and British soldiers, she said she took joint responsibility for a policy that would ultimately see the world as a safer place now and for the next generation.
BBC correspondent Jonathan Beale said the American government had a "loyal ally" in Mr Blair over negotiations aimed at persuading Iran not to develop its own nuclear fuel cycle.
But the US had suffered a setback in talks with Russia, he added.
Moscow gave no indication that it would support a move to refer Iran to the UN Security Council.
"Russia says it has questions about Iran's intentions but insists that Tehran still has a right to enrich uranium," said our correspondent.
Meanwhile, Ms Rice said she would be taking Foreign Secretary Jack Straw to her home city of Birmingham, Alabama next week.