"A number of vulnerabilities in the (current nuclear nonproliferation) system have been exposed in years, and changes are clearly needed if we are to avoid the further proliferation of nuclear weapons," IAEA deputy Director General Olli Heinonen said at a speech he delivered on behalf of the agency Director General Mohamed ElBaradei.

The current nuclear nonproliferation system, based on the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) which was ratified more than 30 years ago, faces a broad array of challenges, he said at the International Nuclear Nonproliferation Science and Technology Forum.

"The increased dissemination of nuclear technology and nuclear 'know-how', renewed drive of a few countries and extremist groups to acquire nuclear weapons and the emergency of clandestine nuclear procurement networks" all posed as challenges, to which the current system needs to address.

To strengthen the nuclear nonproliferation regime, Heinonen said that the access to nuclear fuel cycle technology should be better controlled and the protection of nuclear material should beensured.

"The IAEA and others have been exploring options for how the most sensitive aspects of the nuclear fuel cycle -- uranium enrichment and plutonium separation -- might be implemented," he said.

The UN nuclear watchdog suggested a concept of multinational arrangements to tackle the issue, which consists of four steps. The first is to develop a mechanism to provide a guarantee that reactor technology and nuclear fuel would be available to all bonafide users for peaceful civilian applications. The second step would be to call for a temporary moratorium on new uranium enrichment and plutonium reprocessing facilities. The third and the fourth steps are to establish frameworks for multinational management and control of fuel cycle process.

The speech also called for efforts to protect nuclear material from extremist groups and to support effective nuclear verification.

Besides the IAEA representative, over 20 senior officials and experts from nuclear or energy field of European Commission, France, Japan, Russia, South Korea, the United States will also deliver speeches and discuss over topics including peaceful use of nuclear energy, prospects of nuclear nonproliferation and safeguards technologies during the two-day forum.