Obama in Berlin calls for US-Russia nuclear weapons cuts
US President Barack Obama has called for greater efforts to be made to reduce US and Russian nuclear arsenals.
Speaking at the Brandenburg Gate during a visit to the German capital, Berlin, he said he was confident the US could maintain its security while reducing its nuclear capacity by a third.
He also called for reductions in the number of tactical warheads in Europe.
However Russia's Deputy Prime Minister Dmitry Rogozin said Moscow "cannot take these assurances seriously".
The US and Russian signed a joint agreement in 2010 to mutually reduce their stockpiles of nuclear weapons to a maximum of 1,550 warheads and no more than 700 deployed launchers.
Mr Obama said the US was "on track" to cutting its warheads to pre-Cold War levels, but "we have more work to do".
He 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".
"I intend to seek negotiated cuts with Russia to move beyond Cold War nuclear postures," he said.
"We may no longer live in fear of global annihilation but so long as nuclear weapons exist, we are not truly safe."
Mr 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.
He also said the US rejected the nuclearisation of countries like North Korea and Iran.
But Mr Rogozin, a former Russian ambassador to Nato, said Moscow "cannot take these assurances seriously" while the US is taking steps to build up its missile defence systems.
"The offence arms race leads to a defence arms race and vice versa," he said in comments quoted in Russia's state-owned Itar-Tass
Shortly before Mr Obama spoke, Russian President Vladimir Putin was quoted as saying that Moscow "cannot allow the balance of the system of strategic deterrence to be disturbed or the effectiveness of our nuclear force to be decreased".
A senior foreign policy adviser to Mr Putin said other nuclear-armed countries would have also have to reduce their stockpiles for such a plan to work.
"The situation now is not like in the 1960s and 1970s when only the United States and the Soviet Union held talks on reducing nuclear arms," Yury Ushakov told a briefing in Moscow.
"Now we need to look more broadly... and increase the circle of participants in possible contacts on this matter."
Mr Obama's visit to Berlin is his first as American president.
His address to students and government officials at the Brandenburg Gate, which once divided East and West Germany, comes almost 50 years after President John F Kennedy's celebrated "Ich bin ein Berliner" speech.
Mr 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".
In her morning meetings with Mr Obama, Mrs Merkel had criticised Prism, the recently exposed US phone and internet surveillance programmes, saying: "We do see the need for gathering information, but there is a need for due diligence and proportionality."
The chancellor grew up in Communist East Germany, where police surveillance was widespread.
She acknowledged that the internet "enables enemies of a free liberal order to use and abuse and bring threats to all of us", but "an equitable balance must be struck".
Mr Obama said the monitoring applied within narrow limits to do with national security. It had detected 50 potential threats and saved many lives, he emphasised.
"This is not a situation where we simply go into the internet and begin searching any way we want," he told a news conference in Berlin.
Mr Obama's visit comes after G8 leaders backed calls for holding Syrian peace talks in Geneva "as soon as possible".
Speaking earlier, Mr Obama said the US was confident that the Syrian government had used chemical weapons during the 26-month-old conflict, but refused to spell out what aid might go the rebels.
"I cannot and will not comment on specifics on our programmes related to the Syrian opposition," he said, stressing his support for a political transition.