, WASHINGTON, Apr 12 – President Barack Obama will Monday open an unprecedented nuclear security summit, warning that the atomic aspirations of groups like Al-Qaeda are the top security threat to the United States.
Obama will welcome leaders from 46 other nations to a meeting aimed at safeguarding unsecured uranium and separated plutonium stockpiles and averting the nightmare scenario of extremist groups acquiring nuclear weapons.
On the eve of the largest summit chaired by a US president in 65 years, Obama on Sunday conjured up the horrific possibility of a nuclear detonation in New York City, London or Johannesburg.
"The single biggest threat to US security, both short-term, medium-term and long-term, would be the possibility of a terrorist organization obtaining a nuclear weapon," Obama said on the eve of the two-day summit.
"This is something that could change the security landscape of this country and around the world for years to come."
"We know that organizations like Al-Qaeda are in the process of trying to secure a nuclear weapon — a weapon of mass destruction that they have no compunction at using."
As well as presiding over the summit, Obama will hold a string of bilateral meetings with world leaders.
Key will be his encounter with Chinese President Hu Jintao Monday in talks likely to focus partly on US hopes that China will let its yuan currency find a market level, after a period of Sino-US tensions.
Security blankets Washington as nuclear summit looms
Despite the focus on extremist groups, two states, however, Iran and North Korea, which already has the bomb, will cast a shadow over the two-day summit which opens on Monday.
Washington is leading an effort to toughen sanctions within weeks on Iran over its nuclear program, which the United States and allies say is aimed at producing weapons, a charge Tehran denies.
The White House will seek concrete commitments from world leaders on securing stockpiles of separated plutonium and uranium, to ensure that they cannot be stolen, smuggled or sold to extremists.
"The threat of nuclear war… has diminished. The threat of nuclear terrorism has increased," US Secretary of State Hillary Clinton told ABC News.
To kick off his counter-proliferation drive, Obama met Kazakhstan\’s President Nursultan Nazerbayev and South African President Jacob Zuma.
Kazakhstan handed over Soviet-era nuclear weapons after the end of the Cold War, but is a key player in Washington as it bills itself as the world\’s top exporter of uranium.
South Africa gave up its nuclear weapons program in the 1990s, and US officials praised its example, saying its security had emerged enhanced.
He also held talks with Prime Ministers Manmohan Singh and Yousuf Raza Gilani of nuclear-armed rivals India and Pakistan.
Obama, who last week signed a landmark disarmament treaty with Russia and laid out a new US nuclear strategy limiting how Washington could use atomic weapons, said he was confident that the summit would garner important progress.
"I feel very good at this stage in the degree of commitment and sense of urgency that I\’ve seen from the world leaders so far on this issue," Obama said.
"We think we can make enormous progress on this."
US officials hope nations at the summit will agree a series of their own security steps for their own nuclear material, and help pay to put the stocks of less well-off countries under lock and key.
They also expect some leaders to unveil specific actions, similar to Chile\’s decision to ship a stock of highly enriched uranium to the United States.
The conference is also a precursor to the United Nations Non-Proliferation Treaty review conference next month, seen as another important moment in heading off a future nuclear arms race.
The White House also announced that the US leader would have a meeting with Turkish Prime Minister Recep Tayyip Erdogan.
The talks will occur just over a week after Turkey decided to return its ambassador to Washington after a row over moves in Congress to brand the World War I massacres of Armenians as genocide.
Turkey is also seeking to revive stalled reconciliation efforts with Armenia. Obama may play a part in that effort, when he meets Armenian President Serzh Sarkisian in a separate meeting on Monday.