Iran nuke threat obstacle to global peace: Obama

American President Barack Obama arrived in Turkey Sunday on the last stop of his maiden tour to Europe following a speech in Prague where he laid out his vision for a nuclear-free world just hours after North Korea launched a rocket over Japan.

The two-day visit aimed at revitalizing ties with Washington's long-standing, mainly Muslim ally marks Obama's first trip to a majority Muslim nation since becoming president in January.

Obama flew in to Ankara after attending a European Union summit in Prague where he endorsed Turkey's accession into the bloc, despite opposition from French President Nicolas Sarkozy and guarded remarks from German Chancellor Angela Merkel.

Before the EU summit, he also participated in a NATO gathering jointly hosted by France and Germany, where he was instrumental in winning Turkey's backing to Danish Prime Minister Anders Fogh Rasmussen as the alliance's next leader.

World free of nuclear weapons

Earlier, Obama set out his vision for a world free of nuclear weapons in a speech in Prague that was overshadowed by North Korea's launch of a rocket over Japan hours earlier.

In an open-air speech on the eighth day of his Europe tour, Obama said that eliminating the nuclear threat from Iran would remove the driving force for building anti-missile defenses.

Visiting the Czech capital on a one-week trip marking his presidential debut on the world stage, Obama committed himself to reducing the U.S. nuclear arsenal, bringing the Comprehensive Test Ban Treaty into force and seeking tough penalties for countries that broke the rules on non-proliferation.

"The United States will take concrete steps toward a world without nuclear weapons," he told a cheering crowd.

He said North Korea broke the rules with a rocket launch, which the communist country claimed was intended to put a satellite in orbit, earlier on Sunday and called on Pyongyang to abandon its efforts to acquire nuclear weapons.

The United States will take concrete steps toward a world without nuclear weapons

Barack Obama, speech in Prague

"Iranian threat"

The Czech Republic is one of two sites in eastern Europe for a planned U.S. missile shield that has angered Russia. Washington says the shield is necessary to counter threats from what it calls rogue states, such as Iran.

"As long as the threat from Iran persists, we will go forward with the missile system," Obama said.

"If the Iranian threat is eliminated, we will have a stronger basis for security, and the driving force for missile construction in Europe will be removed."

As long as the threat from Iran persists, we will go forward with the missile system

Obama

Iran is a paper tiger

On Saturday Saudi Arabia's former ambassador to Washington and a former intelligence chief described Iran's government as frail but possessing the tools it needs to achieve "expansionist aspirations at the expense of Arab interests."

"Arab differences represent a main reason for the increased Iranian role in the region that comes at the expense of crucial Arab interests and issues," the Saudi daily al-Watan quotedTurki as saying in a closed door meeting at the University of Jordan's Strategic Studies Center.

"Iran is a paper tiger with claws of steel," he said.

Iran is a paper tiger with claws of steel

Turki al-Faisal, former Saudi Arabian ambassador

Hoping for credibility

Thousands of Czechs and foreign tourists crowded into Hradcanke Square outside the medieval Prague Castle to hear Obama speak. A U.S. official quoted city authorities as estimating the crowd at more than 20,000.

Aides said Obama hoped that calling for a nuclear-free world would lend credibility to Washington's efforts to resolve atomic disputes with countries such as Iran and North Korea.

Earlier, Gary Samore, White House coordinator for arms control, said the North Korean rocket launch meant missile defense would remain a priority.

"The North Korean test illustrates the importance of continuing to develop missile defense in order to protect ... both the country and our allies in Asia," Samore told reporters.

In Prague, Obama planned to discuss climate change and energy security with the leaders of the 27 European Union countries at a summit hosted by the Czech EU presidency.

The North Korean test illustrates the importance of continuing to develop missile defense in order to protect ... both the country and our allies in Asia

Gary Samore, White House coordinator for arms control