Obama calls for one-third cut in US-Russia nuclear weapons

President Barack Obama has called for a one-third cut in the number of deployed United States strategic nuclear warheads if Russia agrees to a similar reduction, reviving his goal to work toward a world without atomic weapons.

Addressing students and government officials at historic the Brandenburg Gate, which once divided East and West Germany, Obama said he had determined that the US could ensure its own and its allies security and maintain a credible deterrent "while reducing our deployed strategic nuclear weapons by up to one third".

"We may no longer live in fear of global annihilation but so long as nuclear weapons exist, we are not truly safe," Obama, currently on his first visit to Berlin as American president, said, calling for intensified efforts to limit their spread.

"I intend to seek negotiated cuts with Russia to move beyond Cold War nuclear postures," he said.

Under the New Start treaty which the US signed with Russia in 2010, each side is allowed a maximum of 1,550 warheads and no more than 700 deployed launchers.

The new limit on delivery systems is less than half the ceiling of 1,600 specified in the original Start treaty from 1991.

Obama added that the US would also work alongside NATO allies to seek "bold reductions" in the use of tactical weapons in Europe, and would also seek to forge a new international framework for the use of peaceful nuclear power.

Obama is seeking to revive the process of nuclear disarmament which figured prominently during his first term but which has largely disappeared from the agenda since then.

Obama's speech, which drew a huge crowd of Germans despite sweltering heat, marked the 50th anniversary of John F Kennedy's message of solidarity to Berliners delivered just two years after the wall’s construction.

In his speech which centred on a theme of freedoms, Obama said the gate was a symbol that "no wall can stand against the yearnings for justice... that burn in the human heart".

"Today's threats are not as stark as they were half a century ago, but the struggle for freedom and security and human dignity, that struggle goes on," he said.

Obama said that for the US, moving beyond the Cold War "mindset of perpetual war" also meant redoubling efforts to close the US prison camp at Guantanamo, tightly controlling the use of new technology like drones and "balancing the pursuit of security with the protection of privacy".