U.S. President Barack Obama reiterated Monday his commitment to reinforcing the Non- Proliferation Treaty (NPT), which he believed is under increasing pressure.

"For four decades, the NPT has been the cornerstone of our collective efforts to prevent the proliferation of these weapons. But today, this regime is under increasing pressure," Obama said in a statement on the Nuclear Non-Proliferation Treaty Review Conference that just kicked off at the UN headquarters in New York City.

"A year ago in Prague, I therefore made it a priority of the United States to strengthen each of the treaty's key pillars as we work to stop the spread of nuclear weapons, and to pursue the peace and security of a world without them," he said.

The NPT is a landmark international treaty whose objective is to prevent the spread of nuclear weapons and weapons technology, to promote cooperation in the peaceful use of nuclear energy and to further the goal of achieving nuclear disarmament and general and complete disarmament.

Outlining his expectations of the review conference, Obama said that "we will see whether nations with nuclear weapons will fulfill their NPT obligations to move toward nuclear disarmament ... whether nations without nuclear weapons will fulfill their obligation to forsake them."

"Nations that ignore their obligations find themselves less secure, less prosperous and more isolated. That is the choice nations must make," he said.

He also promised to "work to ensure that nations that abide by their obligations can access peaceful nuclear energy."