Washington, Apr 14 (DPA): UN Secretary General Ban Ki-moon has urged a high-profile nuclear summit hosted by US President Barack Obama to consider urgent implementation of a five-point plan to reduce the global challenge of nuclear terrorism.

According to a text of his prepared remarks, Ban Tuesday named the steps as: Preventing nuclear terrorism; securing nuclear fissile materials; strengthening the International Atomic Energy Agency (IAEA); engagement by the UN Security Council; and parallel progress in nuclear disarmament and non-proliferation.

"Even one attack could inflict mass casualties and change our world forever," Ban said in an address to the nuclear security summit attended by leaders of 47 nations.

"Such a prospect should compel all of us to strengthen our common defences," he said.

Ban noted his disappointment over lack of support and implementation of programmes already intended to fight nuclear terrorism, such as the International Convention for the Suppression of Acts of Nuclear Terrorism, adopted by the UN General Assembly five years ago. The convention entered into force in July 2007 after a minimum of 22 countries ratified it.

There are now 65 ratifiers of the convention.

But Ban said he was far from being satisfied, given the low level of action compared to the looming threat of nuclear terrorism.

"There is an urgent need for accurate accounting and transparency of all stockpiles of fissile materials, including historical production," Ban said. He called for a reliable international instrument to keep fissile material production in check.

The UN Commission on Disarmament in Geneva has been urged, but has not yet begun negotiations, to formulate a treaty banning production of fissile material for nuclear weapons and other nuclear explosives.

"This is wrong," Ban said.

He said he plans to call for a ministerial-level meeting in September in New York to provide the political will to move ahead with treaty negotiations.

Ban urged the UN Security Council to become more engaged in nuclear issues, from disarmament to non-proliferation, and to achieve progress in both fields. He called for regular high-level meetings on nuclear issues like the one organised last September and presided over by Obama.

That meeting was attended by the council's heads of state and government.

The council has authority over issues of peace and security around the world and its decisions are binding on UN members.

Implementation of the five-point plan would enhance prospects for a stronger Nuclear Non-Proliferation Treaty (NPT), Ban said.

The UN will hold wide-ranging assessments of NPT's effectiveness in curbing nuclear proliferation at UN headquarters, expected to be attended by nuclear and disarmament experts as well as government officials. The three-week conference will begin on May 3, an even that happens every five years.