Thirty-five countries on Tuesday committed to bolstering nuclear security, backing a global drive spearheaded by US President Barack Obama to prevent dangerous materials falling into the hands of terrorists.
In a joint statement issued on the sidelines of the third biennial Nuclear Security Summit (NSS), the countries pledged to work closer together and submit to "peer reviews periodically" of their sensitive nuclear security regimes.
The nations -- including Israel, Kazakhstan, Morocco and Turkey but not Russia -- vowed to "realise or exceed" the standards set out in a series of guidelines laid down by the International Atomic Energy Agency (IAEA) to safeguard nuclear materials.
These are the "closest things we have to international standards for nuclear security", US Energy Secretary Ernest Moniz told reporters as he presented the pledge.
Obama has made improving nuclear safety one of the figurehead foreign policies of his presidency and said in 2009 that nuclear terrorism was "the most immediate and extreme threat to global security".
Frans Timmermans, foreign minister of the Netherlands, which is hosting the summit of more than 50 countries, acknowledged that nuclear security had to remain a "national responsibility" but said closer international cooperation could be "a direct contribution in preventing nuclear material becoming a security risk".
- 'Important accomplishment' -
Dutch Prime Minister Mark Rutte, opening the two-day talks on Monday, said there were "almost 2,000 tonnes of weapons-usable material in circulation worldwide" and stressed that "security has to be our constant concern".
Analysts hailed the joint pledge but voiced concern that not all countries had signed up -- notably Russia, with its outstanding stockpile of Soviet-era weapons.
Miles Pomper, an expert at the California-based James Martin Center for Nonproliferation Studies, said the statement was "the most important accomplishment of the summit".
But he added: "We need to get the rest of the summit members to sign up to it, especially Russia, and we need to find a way to make this into permanent international law."
Shin Chang-Hoon, analyst at the Asan Institute for Policy Studies in South Korea, highlighted the peer review commitment in the pledge as "an important part of nuclear security".
"This will probably be the legacy of the NSS, more than the final communique," he added.
According to a draft final statement obtained by AFP, leaders will push to reduce stockpiles of highly enriched uranium, which can be used to make an atomic bomb, and convert it to safer lower enriched uranium.
Michelle Cann, senior policy analyst at the Partnership for Global Security, said that despite the fanfare surrounding the pledge, "the real question is when the remaining third of states will announce their commitment to these principles too".
The summit has been overshadowed by the crisis in Ukraine, with Obama gathering his G7 allies on Monday to effectively expel Russia from the top table by scrapping a G8 meeting planned in Sochi in June.
UN Secretary General Ban Ki-moon has warned that the West's failure to defend Ukraine from Russian aggression should not be seen as an invitation to other states to acquire nuclear weapons.
Ukraine gave up its huge Soviet-era nuclear arsenal in exchange for guarantees from the West and Russia that its sovereignty would be safeguarded.
These assurances have been "seriously undermined", said Ban. "This should not serve as an excuse to pursue nuclear weapons, which will only increase insecurity and isolation."
The first NSS was held in Washington in 2010, with a follow-up summit in Seoul before this year's event in The Hague.
Washington will again host the final summit in 2016.