More than a dozen countries announced their progress in removing highly enriched uranium (HEU) within their borders on the first day of the third Nuclear Security Summit (NSS), which opened in The Hague Monday.

In a statement issued here Monday, Italy and the United States said that they have jointly completed the removal of approximately 20 kg of excess HEU and separated plutonium from Italy.

Belgium and the United States in a separate statement also said that they have jointly completed the removal of "a significant amount" of excess HEU and separated plutonium from Belgium.

Another joint statement released by leaders of 12 nations, namely Chile, Czech Republic, Denmark, Georgia, Hungary, Mexico, Republic of Korea, Romania, Sweden, Turkey, Ukraine, and Vietnam, highlighted the elimination of HEU in their countries.

These leaders expressed appreciation to Russia, the United States and the International Atomic Energy Agency for "their assistance in converting research reactors from HEU fuel to LEU fuel and in related HEU removal efforts."

The nuclear material removed from these countries will initially be secured and ultimately disposed or "downblended" to low enriched uranium (LEU), according to the joint statement.

The NSS has become an important platform to address nuclear security issues since its first meeting in Washington in 2010. The second meeting was held in Seoul in 2012.

This year's summit aims to prevent nuclear terrorism by reducing the amount of dangerous nuclear material in the world, improving security of all nuclear material and radioactive sources, and stepping up international cooperation.

HEU and plutonium can be used to manufacture nuclear weapons. However, HEU is also used in research reactors and for medical isotope production. Plutonium is used by some countries as fuel for nuclear power plants.

As part of a package of measures dedicated to global nuclear security, the nuclear summits have been urging countries to minimize the use of these materials.

In the four years since the Washington Nuclear Security Summit, NSS participating countries have taken steps to accomplish this goal.