President Bush is in Vienna for a U.S.-European Union summit expected to focus on Iran, terrorism, and trade.
Mr. Bush was greeted at the Vienna airport by summit host and current European Union President, Austrian Chancellor Wolfgang Schuessel.
White House National Security Adviser Stephen Hadley says Mr. Bush and the European powers will reaffirm their efforts to resolve the Iranian nuclear crisis, but says no major announcement are expected.
Iran is currently considering a package of incentives to give up its nuclear program. Mr. Bush says a nuclear-armed Iran would pose a grave threat to all people. But he says Iran will see real benefits if it verifiably suspends uranium enrichment
The Europeans also are expected to raise the issue of closing the U.S. military detention facility at Guantanamo Bay in Cuba.
Summit participants plan discuss trade while negotiators struggle to meet a year-end deadline for a new world trade agreement.
Thousands of demonstrators are expected in Vienna to protest Mr. Bush's visit, the war in Iraq, and some tactics in the war against terrorism.
After Vienna, Mr. Bush heads to Budapest for ceremonies marking the 50th anniversary of the Hungarian Revolution.
Information for this report is provided by AP and Reuters.