PRAGUE (Reuters) - President Barack Obama will call for the elimination of all nuclear weapons across the globe, in remarks on Sunday he hopes will lend credibility to his message in atomic disputes with Iran and North Korea.

President Barack Obama addresses a news conference at the NATO summit in Strasbourg, April 4, 2009. REUTERS/Jason Reed

Visiting Prague during an eight-day visit to Europe, Obama plans to deliver what his aides have billed as a major speech on weapons proliferation.

Obama, who is making his debut on the world stage, said in Strasbourg, France on Friday that he would lay out an agenda to secure the world’s loose nuclear materials and halt the spread of illicit weapons.

He added that he wanted to offer an agenda “to seek the goal of a world without nuclear weapons.”

“Even with the Cold War over, the spread of nuclear weapons or the theft of nuclear material could lead to the extermination of any city on the planet,” Obama said.

Obama, a former U.S. senator who succeeded President George W. Bush in January, has long shown interest in the issue of halting weapons proliferation and wants to make it a signature foreign policy issue for his new administration.

“The president has been very focused on these issues of proliferation for many years,” White House Deputy National Security Adviser Denis McDonough told reporters.

“Tomorrow, I think you’ll hear the president, in a very comprehensive way, outline many of the things that he’s been talking about and working on for some time,” McDonough said.

While in Prague, Obama will also discuss climate change and energy security with the 27 leaders of European Union countries at a summit hosted by the Czech EU presidency, undermined by a government collapse last week.

Thousands of Czechs are expected to turn up for Obama’s speech at a square outside the medieval Prague Castle, with the panorama of the historic Czech capital in the background.

The call for renewed efforts at global nuclear disarmament is likely to be well received in Europe, where Obama is seeking to use his strong popularity to advance his agenda on issues such as Iran and the war in Afghanistan.

The proliferation speech comes after Obama met on Wednesday with Russian President Dmitry Medvedev on the sidelines of the Group of 20 economic summit, where the two leaders pledged to pursue a new deal to cut nuclear warheads.

The aim to is agree to a successor to the 1991 Strategic Arms Reduction Treaty (START 1), which led to the biggest-ever bilateral cuts in nuclear weapons, but expires in December.

Obama is seeking support from Russia, China and other countries to pressure Iran over its disputed nuclear program and ratchet up pressure on North Korea, which has said it will send a satellite into space between April 4 and 8.

The launch is widely seen abroad as a disguised long-range missile test.

The United States and its European allies accuse Iran of planning to build an atomic bomb. But Iran denies this, saying its nuclear program is aimed at the peaceful purpose of generating electricity.

McDonough said Obama will urge a revival of the Nuclear Non-Proliferation Treaty (NPT), which was ratified in 1970 and calls on nuclear states to take steps to disarm and forbids non-nuclear states from trying to acquire them.

“That is an age-old bargain that the president wants to reinforce and it will strengthen our hand with countries like Iran that continue to pursue an illicit nuclear technology,” he said.

George Perkovich, a scholar at the Carnegie Endowment for International Peace think tank in Washington, said that unlike issues such as the economic downturn and the Iraq war, the proliferation agenda is not an issue he inherited from the Bush administration but one he is actively promoting.

“This is one of the few things that is not part of his inheritance,” Perkovich said.

The visit to the Czech Republic, a central European NATO-member country about to commemorate the 20th anniversary of the collapse of communist rule, has been marred by the collapse of Prime Minister Mirek Topolanek’s cabinet.

After losing a no-confidence vote, his government is expected to leave power soon. The Czech government is a close U.S. ally that has sent troops to Iraq and Afghanistan.

Topolanek, who is chairing the European Union in the first half of this year, caused a stir last week when he described U.S. prescriptions to fix the economic crisis as a “road to hell.”

Topolanek plans to ask Obama about plans to build a missile defense radar southeast of Prague, a project firmly backed by the Czech government but opposed by most Czechs.

The Czech radar system and plans to site missile shield bases in Poland have angered Russia but lost pace under Obama’s administration. Obama has told Moscow he is willing to slow the deployment of the system in Europe if Russia helps in curbing Iran’s nuclear ambitions.