UK Prime Minister Tony Blair will meet US President George Bush in April to discuss military action against Iraq, it is reported.
The Observer newspaper says Mr Blair will travel to Washington in six weeks' time for a specially-convened summit on the issue.
It says Mr Blair will support action against Saddam Hussein if the Iraqi leader continues to ignore demands that he destroy his weapons of mass destruction.
Saddam Hussein denies trying to acquire weapons of mass destruction
Downing Street refused to discuss Mr Blair's travel plans but said Britain shared US concerns about Iraq's development of such weapons.
"The meeting will be to finalise phase two of the war against terrorism," the Observer quoted a senior official as saying.
"Action against Iraq will be at the top of the agenda."
The newspaper said the UK Government was planning to publish evidence detailing Iraq's nuclear capabilities to quell any criticism from its backbenches and to reassure the public.
The document is expected to reveal that Saddam Hussein is attempting to amass crude nuclear capabilities, as well as possibly biological and chemical devices.
The Downing Street source told the paper that it was a "public persuasion" issue that was necessary to maintain support for military action against Iraq.
A Downing Street spokesman told the AFP news agency: "We do share the United States' concern about Iraq's funding of terrorism and development of weapons of mass destruction.
"We will consult with all of our allies including the US on the second phase. We remain fully committed to the campaign on terrorism."
French Prime Minister Lionel Jospin - who has previously warned the US against a "fixation" with terrorism - said he had discussed Iraq and the US with Mr Blair and German Chancellor Gerhard Schroeder on Saturday.
The three leaders had talked at the progressive government meeting in Stockholm, Sweden.
"We express the wish that they be with us, that we cooperate with them," Mr Jospin said.
Downing Street was unable to give details of that discussion, but Mr Blair stressed that the coalition remained solid.
"The alliance with the United States is strong, it will remain strong," he said. "We will deal with issues together."
'Axis of evil'
Mr Blair said: "The Americans are absolutely right to emphasise the continuing importance of the war against terrorism and continuing the elimination of weapons of mass destruction."
Mr Bush has demanded that Saddam Hussein allow checks by UN weapons inspectors, who left Baghdad in 1998 ahead of a US-led bombing campaign.
Last month he accused Iraq along with Iran and North Korea of making up a dangerous "axis of evil".
His administration is reported to have decided to force a change of regime in Baghdad.
Saddam Hussein has accused the US of bullying, and said his country would stand firm against attempts to topple his regime.
He also dismissed US accusations that Baghdad had or was seeking weapons of mass destruction as "baby talk".