I thank the Government of the Netherlands for hosting this third Nuclear Security Summit.
Nuclear security remains a pressing concern, not least the risk of nuclear terrorism.
The primary responsibility for preventing non-state actors and terrorists from acquiring the most devastating weapons known to humanity lies with national governments.
But international cooperation and assistance are indispensable.
Important challenges include strengthening nuclear security implementation and building a culture of nuclear security.
I see three areas where the United Nations has an important role to play.
First, strengthening the international framework for nuclear security.
In 2012, I convened a high-level meeting on countering nuclear terrorism in New York.
This was followed in 2013 by the IAEA International Conference on Nuclear Security.
These meetings underscored the need for universal adherence to the relevant international legal instruments.
They also helped to expand recognition of the central role of the IAEA in a strengthened framework for nuclear security.
I am pleased to see this reflected in the communiqué of this Summit.
The IAEA has the mandate and expertise to help States implement their nuclear security-related legal and political commitments.
All States should make full use of the IAEA’s guidance and plans, not just in the realm of nuclear security but also in ensuring the safety of nuclear facilities throughout the world.
The second contribution of the United Nations system is in strengthening the capacity of States to detect and stop illicit trade in nuclear and radiological material.
The United Nations Office on Drugs and Crime, UNODC, has an important role to play.
It can help States to ratify the relevant legal instruments, incorporate their provisions into domestic criminal laws and build capacity to implement them.
As these capacities grow, they will benefit not just individual States but international peace and security overall.
But deeper and more structured global cooperation is needed.
We have much to build on, including the International Convention on the Suppression of Acts of Nuclear Terrorism and the Convention on the Physical Protection of Nuclear Material.
Another important tool is Security Council resolution 1540 on the non-proliferation of nuclear, chemical and biological weapons and their means of delivery.
Supporting its implementation is a key priority of the UN Office for Disarmament Affairs, in cooperation with the IAEA and other organizations. .
For its part, the UNODC is contributing through its Container Control Programme, developed with the World Customs Organization.
I would also like to acknowledge the vital role of Interpol, in particular its rapid and secure law enforcement communication across borders and coordinated multinational action to track individuals involved in trafficking.
Significant contributions to nuclear security have also come from international, regional and sub-regional initiatives, and from industry and civil society.
We should work to further enhance these efforts.
We must also do more to prevent and detect the unauthorized acquisition of material outside of regulatory control.
There is a pressing need to expand training and educational opportunities for customs officials, border agents, police and other relevant authorities.
The third contribution of the United Nations system comes through our persistent efforts to achieve a world free of nuclear-weapons.
Non-proliferation and nuclear material controls are truly important, but neither offers any guarantee against the worst threat of all: a future use of nuclear weapons.
Let me be clear: nuclear security is jeopardized by the very existence of such weapons and the vast amounts of weapons-usable nuclear material in stockpiles outside of any international regulatory controls.
This is why disarmament belongs on the global nuclear security agenda.
The catastrophic humanitarian consequences of any use of nuclear weapons require that it be treated as a top priority.
Disarmament will work better than any alternative in reducing the risk of use.
I welcome the unilateral steps taken by nuclear-weapon States to close facilities once used in nuclear weapon programmes.
Those that have not yet done so should end their production of fissile material for nuclear weapons and also begin to dismantle and convert their facilities.
All nuclear material in weapons programmes must be subject one day to binding international verification.
I call on all States to begin the process now to elaborate effective arrangements.
Clearly the time has come to strengthen the rule of law in both disarmament and non-proliferation.
Commitments to undertake disarmament negotiations in good faith must be honoured.
So, too, must security assurances provided to non-nuclear-weapon States by nuclear-weapon States.
In the case of Ukraine, security assurances were an essential condition for its accession to the Nuclear Non-Proliferation Treaty.
However, the credibility of the assurances given to Ukraine in the Budapest Memorandum of 1994 has been seriously undermined by recent events.
The implications are profound, both for regional security and the integrity of the nuclear non-proliferation regime.
This should not serve as an excuse to pursue nuclear weapons, which will only increase insecurity and isolation.
I call on States parties at the upcoming 2015 NPT Review Conference to address the legitimate interest of non-nuclear States in receiving unequivocal and legally-binding security assurances from nuclear-weapon States.
Together, we must ensure that nuclear weapons are seen by States as a liability, not an asset.
That is why I strongly support ongoing efforts to engage the Islamic Republic of Iran to guarantee that their use of nuclear technology is solely for peaceful purposes.
I also once again urge the Democratic People's Republic of Korea to comply with all relevant Security Council resolutions and resolve the problem by peaceful means.
Today’s meeting on nuclear security continues the very important undertaking of shining a spotlight on this fundamental issue of international safety and stability.
The success of our efforts to prevent another use of a nuclear weapon will involve extensive cooperation on many fronts -- in preventing nuclear terrorism; halting nuclear weapon proliferation; and confronting the risks stemming from the accidental or intentional use of nuclear weapons.
Your presence at this series of Summits is a sign of the growing sense of common purpose.
My message to you now, today, is this: be the first mover.
Do not wait for others to act.
The challenge is one of leadership.
I count on all your contributions.
Let us work towards a safer world for all -- a world free of nuclear weapons and threat of nuclear terrorism.
Please accept my best wishes in all your deliberations.
I am ready to assist in any way to achieve nuclear security.