President Bush criticized unnamed U.S. allies in the Middle East for compromising with extremists and suppressing dissent and called on the Islamic world to move toward democracy as a way to safeguard the United States and reduce violence in the Middle East.

Speaking in front of a waterfront mosque, Bush said that leaders throughout the Middle East, "including some friends of the United States, must recognize the direction of the events of the day. Any nation that compromises with violent extremists only emboldens them and invites future violence.

"Suppressing dissent only increases radicalism. The long-term stability of any government depends on being open to change and responsive to citizens."

Bush did not specify which U.S. allies he was referring to, but an aide and outside experts said that Saudi Arabia was among them. Some U.S. officials have accused the kingdom's government of not working hard enough to suppress al Qaeda cells within its borders.

Bush went on to praise Turkey, a predominantly Muslim nation that became a secular state in 1924, as "a great and stable democracy, and America shares your hope that other nations will take this path."

Bush called a democratic transformation of the Middle East "one of the great and difficult tasks of history."

"Nations in the region will have greater stability because governments will have greater legitimacy," he said. "And nations like Turkey and America will be safer, because a hopeful Middle East will no longer produce ideologies and movements that seek to kill our citizens."

Bush offered no specific new proposals in his speech or details about how he planned to carry out previously announced visions to promote Middle Eastern democracy.

He spoke after leaving the closing session of a two-day NATO summit, where he listened as Afghanistan's U.S.-backed president, Hamid Karzai, said NATO needed to accelerate the deployment of additional troops in his country to secure elections scheduled for September. And the number of those troops, he said, needed to exceed the force already pledged. NATO said it would add 2,200 troops to its current force of 6,500 and keep 1,200 to 2,000 more on reserve outside the country.

"I would like you to please hurry . . . in Afghanistan: Come sooner than September," Karzai pleaded.

Bush's visit to Turkey was tense from beginning to end, with massive protests and security precautions wherever he went. One major breach of security was reported: A small bomb exploded Tuesday aboard a Turkish Airlines passenger jet parked at the Istanbul airport several hours after Bush had departed.

The device was concealed in a leather wallet left on the cabin floor near the door of the aircraft, which had arrived from the Turkish port of Izmir. The explosion injured three aircraft cleaners. There was no assertion of responsibility.

A major theme of Bush's speech was to encourage Iraq, a predominantly Muslim country where an interim government assumed power Monday, to develop a secular democracy that includes protections for minority religious groups. He called for similar changes in Iran and Syria.

"The rise of Iraqi democracy is bringing hope to reformers across the Middle East," he said. "A free and sovereign Iraq is a decisive defeat for extremists and terrorists, because their hateful ideology will lose its appeal in a free and tolerant and successful country."

Bush singled out Iran as a theater for the "struggle between political extremism and civilized values," saying that "tired, discredited autocrats are trying to hold back the democratic will of a rising generation."

In a speech to the National Endowment for Democracy in November, Bush announced a "forward strategy of freedom" committing the United States to a decades-long mission to encourage worldwide democracy. Arab countries have not embraced Bush's challenges.

Bush spoke against the backdrop of the Bosporus Bridge, which spans the Bosporus Strait that divides the European and Asian shores of Istanbul. Turkish warships were anchored in the rippling water behind him, and blasts from boat horns interrupted the speech at Galatasaray University, which was founded in 1481 to train civil servants for the Ottoman Empire.

The White House tried to play up the historical flavor of the setting by renting Ottoman-style chairs with gold-painted backs.

The audience of about 230 people, most of them Turkish officials and their spouses, listened in silence, which a U.S. Embassy official characterized as a sign of respect. The crowd applauded politely at the end of the 27-minute address.

Bush, completing a five-day trip that began in Ireland, repeated his controversial demand that the European Union admit Turkey. "Including Turkey in the EU would prove that Europe is not the exclusive club of a single religion, and it would expose the 'clash of civilizations' as a passing myth of history," he said.

Some European leaders have taken offense at what they consider Bush's meddling. President Jacques Chirac of France publicly rebuked him Monday, saying Bush's stance was "like me telling the United States how to run its affairs with Mexico."

Bush's presumed Democratic opponent in the November election, Sen. John F. Kerry of Massachusetts, obliquely criticized Bush for his closeness to Saudi Arabia during a speech last month in Seattle, in which he called for reducing U.S. dependence on oil from the Middle East.

"For too long, America has lost its voice when talking about the policies and practices of some governments in the Persian Gulf," Kerry said. "This is a weakness that this administration has ignored."

Bush said there was a "wariness toward democracy" in the Middle East. "Some people in Muslim cultures identify democracy with the worst of Western popular culture and want no part of it," he said. "I assure them, when I speak about the blessings of liberty, coarse videos and crass commercialism are not what I have in mind. There is nothing incompatible between democratic values and high standards of decency."

Bush said he was not trying to impose his own values on others. "All people in a democracy have the right to their own religious beliefs," he said. "But all democracies are made stronger when religious people teach and demonstrate upright conduct: family commitment, respect for the law and compassion for the weak."

"Whatever our culture differences may be," Bush said toward the end of his address, "there should be respect and peace in the house of Abraham." That was a reference to the common descent claimed by Christians, Muslims and Jews through the religious patriarch Abraham.

Correspondent Karl Vick contributed to this report.

In Istanbul, President Bush said, "Suppressing dissent only increases radicalism." Bush did not specify which U.S. allies he was criticizing.