Speaking in front of the Prague Castle just hours after the North Korean launch, Obama vowed to immediately seek U.S. ratification of a ban on nuclear testing, convene a summit in Washington to stop the spread of nuclear material within four years and create a nuclear fuel bank to allow peaceful development of nuclear power.
"I state clearly and with conviction America's commitment to seek the peace and security of a world without nuclear weapons," Obama said to a crowd of about 20,000 packed into the historic square in the Czech Republic's capital city. "This goal will not be reached quickly -- perhaps not in my lifetime. It will take patience and persistence. But now we, too, must ignore the voices who tell us that the world cannot change."
The president denounced North Korea's launch of a three-stage Taepodong-2 missile, which flew over Japan before apparently falling into the Pacific Ocean, as a provocative act in defiance of the United Nations.
North Korea has called the launch part of a "peaceful" research project, but the United States, Japan and other allies see it as a threat. The missile has the range to reach Hawaii and Alaska.
Obama said Sunday North Korea risks further isolation by pursuing nuclear weapons and the missiles to carry them.
"Rules must be binding. Violations must be punished. Words must mean something," he said to loud applause. "The world must stand together to stop the spread of these weapons."
White House officials said it was unclear whether the rocket launch was intended to coincide with the president's speech. But intentional or not, it served as a reminder of the potential dangers of nuclear weapons and the difficulty in restraining nations from developing them.
Obama spoke against a backdrop of the city where Soviet and Warsaw Pact forces crushed a movement of political liberalization in August, 1968. His address put new focus on disarmament and nonproliferation issues, which he had also raised in his foreign policy speeches during the presidential campaign.
The scene of his address, under a hazy sky in one of Eastern Europe's oldest and most beautiful cities, recalled Obama's speech in Germany in the midst of the presidential campaign last year.
Thousands of people waved U.S. and Czech flags and chanted "Obama" as they waited for his arrival, packing Hradcany Square, a hilltop plaza outside Prague Castle, to catch a glimpse of the American president. Unlike Obama's other appearances in Europe, his Prague speech was open to the general public; people started lining up before dawn to get a space on the square.
"It was a historical moment, to have him speak here," said Michaela Dombrovska, 32, a civil-servant from Prague. "He's given us hope that American will lead us to more world peace. He's clearly thought up new and different ideas about how to get rid of nuclear weapons in an effective way."
