Thirty-five countries pledged Tuesday to step up nuclear security, backing a global drive spearheaded by US President Barack Obama to prevent dangerous materials falling into the hands of terrorists.
Wrapping up the third biennial Nuclear Security Summit (NSS), which gathered together 53 countries, Obama urged world leaders to work closer together to stop nuclear terrorism that he dubbed "the most immediate and extreme threat to global security".
"It is important for us not to relax but rather accelerate our efforts over the next two years, sustain momentum so that we finish strong in 2016", said the US leader, when he will host a return meeting.
"Given the catastrophic consequences of even a single attack, we cannot afford to be complacent," he stressed.
Dutch Prime Minister Mark Rutte, hosting the talks, said that "major steps" had been taken in terms of the three main goals of the summit: reducing the amount of dangerous nuclear material; improving the security around this material and bolstering international cooperation on the nuclear issue.
And in a joint statement unveiled with much fanfare on the sidelines of the NSS, 35 of the 53 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.
But experts cautioned that the deal lacked teeth without the agreement of other powers with large nuclear stockpiles.
"The absence of Russia, Chain, Pakistan and India -- all nuclear weapons states with large amounts of nuclear material -- as well as others, weakens the initiative's impact," said the Fissile Materials Working Group, a collection of more than 70 experts on the nuclear issue.