President Barack Obama said the U.S. and Turkey can forge a model partnership of secular democratic nations to bridge the divide between Muslim nations and the West.
In his address to the Turkish parliament Monday, Mr. Obama said the predominantly Muslim country is not where East and West divide, it is where they come together.
He expressed strong support for Turkey's bid to become a European Union member, calling Ankara a "resolute ally and responsible partner" in trans-Atlantic and European institutions.
The war in Iraq has strained relations between the NATO allies in recent years. Washington is looking for Turkish help as it expands its campaign in Afghanistan.
Mr. Obama said the United States and Turkey both are threatened by terrorism, and that they must work together to tackle extremism, weapons proliferation and the economic crisis.
He pledged support for Turkey's fight against PKK Kurdish militants, and he applauded Ankara's efforts to lift bans on teaching and broadcasting Kurdish.
At a news conference with Turkish President Abdullah Gul, Mr. Obama addressed Turkey's long-contentious relations with Armenia.
Asked if he had changed his view that the killing of Armenians by Ottoman Turks early last century was genocide -- a charge Ankara rejects -- Mr. Obama replied that he had not. But he added that Washington should not interfere in any negotiations between Turkey and Armenia on that issue.
President Gul said the matter is a historical issue, not a legal one, but that Turkey would welcome an investigation into the question, and that he would accept the findings.
Mr. Obama also said the U.S. supports a resolution of the status of Cyprus, which is divided between ethnic Turks and Greeks.
While in Turkey, the U.S. president also is meeting Prime Minister Recep Tayyip Erdogan.
Turkey is the final stop on Mr. Obama's European tour, which included an economic summit in London last week, NATO meetings in France and Germany, and an EU-U.S. summit in the Czech Republic.