The US made clear on Sunday that Afghanistan would be the exclusive focus of the first phase of its war on terrorism as more of its forces moved into positions to mount strikes inside the country.

US officials said President George W. Bush had decided that the US campaign would initially deal with Osama bin Laden, the prime suspect in the September 11 attacks, and his Afghanistan-based Al-Qaeda network.

They said they attached no credibility to statements by the Taliban leadership in Afghanistan that Mr bin Laden was missing. But they left open the possibility of military action against other states.

US officials said there had been a debate within the administration about whether to target countries other than Afghanistan - principally Iraq - with military action, but that was settled by the president with a decision to focus initially on Afghanistan.

Some differences of approach were still evident, however. Donald Rumsfeld, defence secretary, told CBS television: "The mission determines the coalition and we don't allow coalitions to determine the mission."

Yet Mr Powell made almost the opposite point, stressing the importance of keeping a broad coalition together.

British officials have said that the administration had made plain in meetings with Tony Blair, UK prime minister, that it wanted a tight military coalition in Afghanistan, with operations conducted largely - perhaps wholly - by US and British forces. Mr Rumsfeld said there was no way that the network responsible for the September 11 attacks could have done it without the support of governments, corporations and other organisations.

Officials have suggested that the US might overlook past sponsorship of terrorist organisations not linked to the September 11 attacks in return for future co-operation. "What we are looking at today is how are these states going to behave going forward," Mr Rumsfeld said.

He said that the US was getting help from sources that were surprising. Other officials said co-operation was possible with Iran and Syria, both on the State Department list of state sponsors of terrorism.

With the full support of the US, officials of the European Union on Monday start a six-day, six-nation trip to the Middle East and Pakistan, including Iran and Syria.

Mr Powell said that the US would soon put out a document about Mr bin Laden "that will describe quite clearly the evidence that we have linking him to this attack".

White House officials said they expected the president to issue an executive order on Monday that would tackle the financial underpinnings of terrorist networks, and allow the freezing of bank accounts associated with groups it would name. Senior officials said the US was considering an approach to the United Nations for help with this issue.

Mr Bush signed the order on Saturday to lift 1998 nuclear-related sanctions on India and Pakistan. The US also welcomed the decision by the United Arab Emirates, one of three countries to recognise the Taliban government in Kabul, to cut off diplomatic relations with the regime.