The two-day gathering is the largest called by an American president since Franklin D. Roosevelt organised the 1945 meeting that created the United Nations, the US press reports.
According to the guest list, Europe was represented by Van Rompuy and a number of national leaders, including Belgian Prime Minister Yves Leterme, Czech Prime Minister Jan Fischer, French President Nicolas Sarkozy, German Chancellor Angela Merkel, Italian Prime Minister Silvio Berlusconi, Dutch Prime Minister Jan Peter Balkenende, Polish Foreign Minister Radosław Sikorski, Spanish Prime Minister José Luis Rodriguez Zapatero, Swedish Prime Minister Fredrik Reinfeldt and British Foreign Secretary David Miliband.
The Washington summit is the culmination of a hectic week of nuclear diplomacy for Obama and comes a year after he laid out his vision of a world free of atomic weapons in Prague (see 'Background').
The US administration hopes that the summit will strike an agreement to secure the world's stockpiles of plutonium and highly-enriched uranium (HEU) – essential ingredients in building nuclear weapons – by 2013.
The BBC quotes Rolf Mowatt-Larssen, a former investigator at the CIA and the US Department of Energy, as saying that there are three headlines that keep Obama awake at night:
- 'Loose Pakistani nukes' falling into the hands of terrorists;
- North Korea supplying terrorists with nuclear bombs, and;
- Al-Qaeda launching a nuclear attack.
Ahead of the summit, the US president held a marathon series of bilateral meetings with the leaders of Kazakhstan, South Africa, India, Pakistan, Ukraine, China, Jordan, Armenia and Malaysia.
"I feel very good at this stage on the degree of commitment and a sense of urgency that I have seen from the world leaders so far on this issue […] We think we can make enormous progress on this, and this then becomes part and parcel of the broader focus that we've had over the last several weeks," Obama was quoted as saying.
According to analysts, the summit would not address a new nuclear arms race between India and Pakistan, because the issue is divisive.
Ukraine gives Obama a present
The greatest step forward appears to have been taken by Ukraine, whose pro-Russian President Viktor Yanukovich announced that Kyiv would give up its stockpile of nuclear grade uranium. "Today, at the Nuclear Security Summit, Ukraine demonstrated its leadership, announcing a landmark decision to get rid of all of its stocks of highly-enriched uranium by the time of the next Nuclear Security Summit in 2012, while the United States will provide necessary technical and financial assistance," a summit fact sheet said.
Ukraine intends to remove a substantial part of those stocks this year. It will also convert its civil nuclear research facilities to operate with low-enriched uranium fuel that cannot be used for nuclear weapons, a practice which is fast becoming the global standard this century.
China makes little progress on Iran
In contrast, a meeting between Obama and Chinese President Hu Jintao appears to have made scant progress on agreeing to impose potential sanctions against Iran. White House national security aide Jeff Bader said Iran was a major topic of discussion during hour-long talks between Obama and his Chinese counterpart.
According to the White House, Obama and Hu agreed to instruct their governments to work together on devising potential sanctions designed to punish Iran for its nuclear programme. But China described the outcome differently, without referring to sanctions.
Turkey won't back Iran sanctions
Turkish Prime Minister Recep Tayyip Erdogan declined to support Obama's push for tough new sanctions against Iran but said his country was willing to act as a mediator in the diplomatic standoff over Tehran's nuclear ambitions.
Erdogan said Turkey had enjoyed a strategic alliance with Iran since the 17th century and would prefer to see the deadlock resolved diplomatically. While in Washington to attend the Obama administration's summit on nuclear security, Erdogan spoke to CNN's Christiane Amanpour and said: "I believe that we can find a way out."
In the meantime, Iranian Ambassador to the International Atomic Energy Agency (IAEA) Ali Asghar Soltanieh lashed out at the nuclear summit, saying any decision taken at the conference must not be binding on nations absent from the event.
"The outcome of the Washington conference is already known. Any decision taken at the meeting is not binding on those countries who are not represented at the conference," Soltanieh told the ISNA news agency.
