The International Atomic Energy Agency hosted ministers from all 159 member states at a nuclear security conference in Vienna.
Delegates to the meeting agreed on a declaration stressing a clean energy future depends in large part on a secure energy future.
"We encourage all states to maintain highly effective nuclear security, including physical protection, for all nuclear and other radioactive material," the declaration said.
The International Energy Agency last week said energy resources like natural gas and nuclear power will decline in use as alternative options like wind and solar power come on stream. Nevertheless, U.S. Energy Secretary Ernest Moniz said Monday nuclear energy still plays a role in efforts to combat climate change.
"Nuclear energy is a key part of addressing climate change, and ensuring nuclear security is integral to the expansion of carbon-free nuclear generation," he said in his prepared remarks.
President Obama in June outlined a new climate agenda for his second term encouraging the use of alternative energy resources.