President Bush is in Istanbul for a NATO summit expected to focus on Iraq and Afghanistan.
The president arrived in Istanbul under extremely tight security, forgoing a planned motorcade from the airport for a helicopter ride into the city.
It was a clear sign of the tensions in this country that straddles Asia and Europe, and has been feeling the aftershocks of the violence in neighboring Iraq.
There have been terrorist bombings in recent days in Turkey, and on Saturday came the news that three Turkish workers had been taken hostage in Iraq and threatened with death by their captors.
As he sat down for one-on-one talks with NATO Secretary General Jaap de Hoop Scheffer, President Bush was asked if the kidnapping might cast a pall over the Istanbul summit. He shook his head and mouthed the word no.
But the president did speak about the new challenges facing the alliance - a reference to the war on terrorism. "I was hoping to change the mission of NATO so it meets the threats of the 21st century, and we are going to work together to help make sure NATO is configured militarily to meet the threats of the 21st century, as well," he said.
Mr. Bush has two goals here in Turkey. The first is to see NATO adopt, at least in principle, a plan to help train and equip a new Iraqi security force. The other is to bolster relations with Turkey, the only Muslim nation in the alliance.
Shortly after his arrival in Istanbul, the president met with a group of Turkish religious leaders representing three faiths: Islam, Christianity, and Judaism.
"They represent the very best of Turkey, which is a country that is secular in its politics and strong in its faith," said Mr. Bush.
Mr. Bush expressed similar sentiments earlier in the day during a stop in Ankara, the Turkish capital. It was a visit of substance and symbolism.
The president got a red carpet official welcome, and paid his respects to the founder of modern Turkey at Ataturk's mausoleum. He also met with current Turkish leaders, and praised their government. Turkey's ruling party has Islamist roots.
Relations between Washington and Ankara were tested during the war in Iraq. Turkey refused to grant American warplanes access to its air bases during the war. And there is concern in Ankara about pushes for autonomy for Iraq's Kurdish minority, since Turkey has a Kurdish population of its own.
But a senior Bush administration official, who spoke to reporters on the condition he would not be identified, portrayed the talks in Ankara in very positive terms.
He said whatever differences the United States and Turkey may have had in the past about Iraq have now been put aside. He said Turkey believes its interest in Iraq is parallel to that of the United States and that both sides want to see a stable and successful Iraq that is at peace with its neighbors and respects minorities.
The official went on to note that President Bush brought up the fate of the Turkish hostages in Iraq during his meetings with Prime Minister Erdogan and President Sezer. He said Mr. Bush made clear that this episode shows the true nature of the enemy in the war on terrorism and expressed his sympathies to the Turkish leaders.
The warm words exchanged in Ankara stood in sharp contrast to the mood in some parts of Istanbul, where tens of thousands of protesters demonstrated against the U.S. policy in Iraq. There was a heavy police presence, but there have been no reports of violence.