Obama calls for U.S., Russia to cut nuclear warhead supply

(CNN) -- President Barack Obama will ask Russia to join the United States in slashing its supply of strategic nuclear warheads by about one-third, a senior administration official said.

Obama will announce the goal during a speech Wednesday in Berlin -- a city rife with Cold War history.

The president will also outline his goal to reduce U.S. and Russian tactical nuclear weapons in Europe, the official said. The president hopes to work with NATO allies on proposals toward that goal.

It's all part of Obama's "vision of achieving the peace and security of a world without nuclear weapons," the official said.

"We will seek to negotiate these reductions with Russia to continue to move beyond Cold War nuclear postures," the official added.

Obama's speech will take place almost exactly 50 years after President John F. Kennedy delivered his "Ich bin ein Berliner" -- or "I am a Berliner" -- speech in the city that was divided by Western and Soviet occupations during the Cold War.

Berlin is also where President Ronald Reagan's delivered a famous line to the Soviet Union in 1987: "Mr. Gorbachev, tear down this wall!"

Beyond New START

Obama's latest proposals come two years after New START -- a nuclear agreement between the United States and Russia -- went into effect. New START, which stands for strategic arms reduction treaty, calls for both countries to limit their nuclear warhead arsenal to 1,550 by the year 2018.

Obama's proposals Wednesday would reduce both stockpiles by another one-third -- to roughly 1,000 warheads for each country.

U.S. guidance on nukes

After New START was ratified, Obama ordered a detailed internal analysis of U.S. nuclear needs and what it would take to deter other countries from attacking, the White House said.

"The president has determined that we can ensure our security and that of our allies and partners ... while safely pursuing up to a one-third reduction in deployed strategic nuclear warheads below the New START treaty level," the administration official said.

Obama has also said the United States will only consider the use of nuclear weapons in extreme circumstances to defend the vital interests of the United States or its allies and partners, the White House said.

Pressuring Iran and North Korea

The United States will continue working to stop the spread of nuclear weapons, with specific pressure on Iran and North Korea, the administration official said.

Obama will also participate in the 2014 Nuclear Security Summit in The Hague and will host a Nuclear Security Summit in 2016 to work with other countries in securing nuclear materials and preventing nuclear terrorism, the official said.