During his weekly address on Saturday morning, U.S. President Barack Obama said that no terrorist organization has succeeded to date in producing a dirty bomb or obtaining a nuclear device using radioactive materials, even though al-Qaeda has attempted to.

The president gave his address from this week’s Nuclear Security Summit in which world leaders had gathered to talk about what is described by Obama as one of the biggest threats to world security – terrorists putting their hands on weapons of mass destruction.

On Friday, Obama said that efforts worldwide to stop terrorist groups and others from the use of nuclear weapons had not finished.

The U.S. President ended the summit held in Washington by saying that world leaders made meaningful and significant progress over the past six years in the securing of stockpiles of different nuclear materials.

He added that material sufficient to build 150 nuclear weapons had now been put away safe from terrorists.

However, he added that nuclear arsenals in certain countries were growing and that plutonium stock was increasing.

Obama said that he and over 50 other leaders across the globe had agreed in Washington to strengthen even further the nuclear facilities from any cyberattacks and to improve the intelligence sharing that helps to make sure that dangerous materials do not get into the hands of terror organizations like Islamic State.

President Obama noted that over one dozen nations disposed of their complete supplies of highly enriched plutonium and uranium, the two radioactive elements there are necessary in the building of a nuclear bomb.

During the six years of meetings held with international leaders related to nuclear security, included four such summits, which Obama initiated, the president of the U.S. said we have embraced a new form of thinking and a new form of action.

Obama met as well with a smaller group of the countries that were the most involved in the nuclear agreement in 2015 with Iran. He said the P5+1 group deal with Iran achieved good success and focused on dangers that are involved with nuclear proliferation.