Defence Secretary Donald Rumsfeld is beginning an extended trip to the region which will also include visits to Europe and the Persian Gulf.

Donald Rumsfeld's visit will take in Pakistan, India, Europe and the Gulf

He is due to make his first stop in Britain on Wednesday, where he is scheduled to meet Prime Minister Tony Blair and Defence Secretary Geoff Hoon.

Meanwhile Richard Armitage, the US Deputy Secretary of State, is due in Islamabad for talks on Thursday before flying on to Delhi on Friday.

The BBC's Pentagon correspondent Nick Childs says Washington defence officials remain tight-lipped about aspects of Mr Rumsfeld's mission, including details of exactly when he will be in each country.

Nato meeting

After leaving London, he will fly to Brussels for meetings at Nato headquarters, including the first meeting of the Nato-Russia Council, which was created last month to involve former Cold War enemy Russia in the Western alliance.

My hope is that two countries as important as India and Pakistan will figure out ways to get from where they are to where the world would like them to be

Donald Rumsfeld

After a stop at Geilenkirchen Air Base in Germany to thank Nato aircraft crews for their help in patrolling US skies in the aftermath of the 11 September attacks, Mr Rumsfeld will fly to Estonia for a meeting with defence ministers from the Baltic and Nordic nations.

The defence secretary is also due to visit Kuwait, Qatar and Bahrain, where the danger posed by Iraq's nuclear ambitions is likely to be a topic of discussion.

Mr Rumsfeld will visit India and Pakistan either before or after the Gulf states.

He insisted he was not going to mediate between Islamabad and Delhi, and that his message would depend on how events unfold over the next few days.

Putin also hopes to mediate between India and Pakistan

"It is not possible to know how things will play out, but my guess is, and certainly, my hope is that two countries as important as they are will figure out ways to get from where they are to where the world would like them to be," he said.

The defence secretary's message to both the Indians and the Pakistanis is likely to mention the casualties a nuclear conflict could cause.

A recent Defence Intelligence Agency study concluded that a nuclear exchange between the two countries could kill as many as 12 million people on both sides, with another two million to six million injured.