 Terrorists and criminals will try to exploit any vulnerability in the global nuclear security system. A stark warning from the head of the IAEA at the opening of an international conference on nuclear security. The agency advises countries how to guard against nuclear terrorism and prevent theft and smuggling of radioactive materials. We know that criminal groups have tried to get hold of nuclear material or radioactive material for criminal purposes. Nuclear security is the responsibility of individual countries, but the IAEA provides practical assistance supplying expert advice, equipment and training. Much progress has been made in improving nuclear security throughout the world, but we can never relax our guard. Continued vigilance is essential as the threat evolves. The conference was attended by 2,000 participants from 130 countries. Together they discussed ways to further strengthen global nuclear security and make the world a safer place. From Vianostria, this is Alexandra Anapanich reporting for the IAEA.