President Barack Obama will urge European allies to support the new US strategy for Afghanistan, telling Nato partners this week their security could be at risk if the country falls into chaos.
Making his first major foreign trip since taking office on January 20th, Mr Obama will discuss the economic crisis at the London Group of 20 summit of major economic powers on Thursday. He will then attend the Nato summit in Strasbourg, France, on Friday and Saturday, marking the alliance's 60th anniversary.
This week, Mr Obama unveiled a plan for Afghanistan, where violence is at its highest level since US-led forces toppled the Taliban in 2001 and where the Nato mission has been criticised for disorganisation.
The strategy broadens the US focus to include Pakistan and puts as the highest priority the defeat of al-Qaeda militants who he said were plotting new attacks on the United States. Mr Obama will send 4,000 more US troops to help train the Afghan army and will add more civilian personnel to help tackle problems such as a booming narcotics trade and government corruption.
But Mr Obama emphasised that international cooperation was crucial to the plan's success and promised to take that message to Europe, where the public has grown increasingly impatient with the Afghanistan effort.
"The world cannot afford the price that will come due if Afghanistan slides back into chaos or al Qaeda operates unchecked," Mr Obama said in a speech in Washington on Friday.
"What's at stake now is not just our own security - it is the very idea that free nations can come together on behalf of our common security. That was the founding cause of Nato six decades ago. That must be our common purpose today," he added.
In a shift that has been welcomed in Europe, the Democrat president has promised a more consultative foreign policy than that of his Republican predecessor, George W. Bush. His administration hopes Mr Obama's popularity abroad will raise the profile of his push for greater support for Afghanistan.
In preparing the new Afghanistan strategy, Mr Obama launched a 60-day review that included input from European allies as well as other countries with a stake in the region.
Mr Obama said that from Nato allies, he hoped for "not simply troops, but rather clearly defined capabilities," including support for the Afghan elections, training of security forces and increased civilian support.
Mr Obama's schedule at the Strasbourg summit will include bilateral meetings with President Nicolas Sarkozy and Chancellor Angela Merkel. He will have a lengthy bilateral session in London with Prime Minister Gordon Brown.
On the sidelines of the Nato summit, he will also set aside time to interact with the public during a speech and question-and-answer session with students from various parts of Europe.
After the summit, Mr Obama will attend a gathering of 27 European Union heads of state in Prague, where he also plans to deliver what his aides are billing as a major speech on nuclear proliferation. Looming over the Prague meeting will be the issue of missile defence. A US plan to place a missile defense system in Poland and the Czech Republic has angered Moscow.
Mr Obama has suggested the US would have no need to deploy proposed missile defenses in Eastern Europe if Moscow could help stop Iran from developing long-range weapons.