June 9 (Bloomberg) -- President George W. Bush today reinforced U.S. policy that a strong dollar is in the national interest and said he will appeal to Europe for a greater commitment of aid to Afghanistan.

``I'll talk about our nation's commitment to a strong dollar,'' the president said at the White House before leaving on an eight-day visit to Europe. ``A strong dollar is in our nation's interests. It's in the interest of a global economy.''

Bush said the U.S. economy ``is large and it's open and flexible. Our capital markets are some of the deepest and most liquid, and the long term health and strong foundation of our economy will shine through and be reflected in currency values.''

Bush said the U.S. economy is ``continuing to grow in the face of unprecedented challenges.''

Bush is leaving for Slovenia to attend the annual U.S.- European Summit. The journey will include stops in Germany, Italy, the Vatican, France and Britain on what may be his final visit to Europe as president.

First Lady Laura Bush made a surprise visit to Afghanistan yesterday in a U.S. show of support and to gauge progress in reducing violence and improving economic development in the struggling democracy. During her visit, 19 people, including an Afghan journalist for the BBC, were killed, Agence France- Presse reported.

Aid Sought

Afghanistan President Hamid Karzai is seeking $50 billion over five years from about 80 countries meeting at a donor conference in Paris to aid agricultural and economic development in his country, the New York Times reported June 7.

Mrs. Bush is scheduled to speak on behalf of that effort in Paris on June 12, AFP said.

``She saw progress, but she also saw there is a lot of work to be done,'' the president said, citing a telephone call with his wife, who is now in Slovenia.

There's concern in Europe, though, that Karzai is a weak leader and doesn't have the ``trust and the backbone'' to address Afghanistan's troubles, such as drug trafficking, the New York Times said , citing an unnamed U.S. State Department official.

To contact the reporter on this story: Roger Runningen in Washington at rrunningen@bloomberg.net

Last Updated: June 9, 2008 07:55 EDT