An international summit on nuclear security has concluded in Washington with a pledge to eliminate or safeguard all vulnerable nuclear materials within four years. President Obama announced the goal during his closing remarks.

President Obama: “I am very pleased that all the nations represented here have endorsed the goal that I outlined in Prague one year ago: to secure all vulnerable nuclear materials around the world in four years time. This is an ambitious goal, and we are under no illusions that it will be easy, but the urgency of the threat and the catastrophic consequences of even a single act of nuclear terrorism demand an effort that is at once bold and pragmatic, and this is a goal that can be achieved.”

The final statement from the forty-seven-nation summit also outlines a voluntary action plan to combat nuclear terrorism and promises greater efforts to block non-state actors from developing nuclear weapons. But it glosses over whether to continue making weapons-grade uranium and plutonium and offers no legally binding commitments for enforcement.