Fourth, although the US and Russia promised to reduce their nuclear warheads, they are still modernizing their nuclear arsenals. It means that both sides are trying to optimize the structure and function of their nuclear power to adjust to a greater number of targets. Nuclear weapons are still the most potent and core measures of each nation's military power.

Fifth, although China and Russia have issued a joint statement that they would not be the first to use nuclear weapons against each other, there is no such an agreement between the US and Russia.

Sixth, according to media reports, the US Department of Defense would highlight in their upcoming nuclear review report that the US will continue to implement nuclear deterrence to cope with several current or future threats. This doesn't reflect US President Barack Obama's pledge of realizing a nuclear weapon-free world.

Furthermore, as the US develops its anti-missile system, it is still clinging onto the possibility of deploying a weapons system in outer space. The US claims that its development of an anti-missile system aims at avoiding retaliation but this is the first time a country has attempted to gain strategic advantages in offense and defense since nuclear weapons began to appear. The US' stance undermines the international consensus of the continual process of nuclear disarmament.

Making the process of nuclear disarmament irreversible and realizing the magnificent target of completely destroying nuclear weapons globally depends on global and regional strategic stability and practical measures to promote universal security in all the countries.

To safeguard the globe and not endanger the security of each country, nuclear powers should begin discussing more measures of arms control. First, they should agree to support the role of the United Nations. Nuclear powers should safeguard the authority of the UN and its security council on arbitrating international disputes.

Second, nations should reduce the role of nuclear arms in national security strategies, cease the development of new nuclear weapons and put the Comprehensive Nuclear Test-Ban Treaty into effect.

Third, they should promise to deactivate nuclear weapons, and retrieve any nuclear weapons stationed in other countries.

Fourth, they should begin negotiating a treaty to prohibit any weapons system in space.

Fifth, they should promise to stop developing and deploying Ballistic Missile Defense Systems that undermine strategic stability. Sixth, they should promote the Conference on Disarmament in Geneva and reach a treaty to stop the production of radioactive materials used in weapons.

Lastly, they should try to establish feasible international arrangements generally accepted by various countries for the supply of nuclear fuels and the disposal of spent fuels.The international community expects nuclear powers to fulfill their promise in promoting nuclear disarmament and reducing the risk of a nuclear war. If the five nuclear powers can reach a consensus at the Review Conference this May that they will not be the first to use nuclear weapons, it will greatly influence the process of the review conference.

Reducing the role of nuclear weapons is key to making the process of nuclear disarmament irreversible. Nuclear powers regard their nuclear weapons as a defensive response to a nuclear strike, but this viewpoint increases the likelihood of using these weapons. It also greatly threatens international security and stability. If nuclear powers can fulfill the promise of not being the first to use nuclear weapons, it will be equal to the joint commitment of not using nuclear weapons at all. In the long run, it's conducive to realizing the goal of complete prohibition and destruction of nuclear weapons.

The author is a senior research fellow of China Arms Control and Disarmament Association.