The Nuclear Non-Proliferation Treaty (NPT) should be strengthened to cope with present-day challenges that endanger global nuclear security goals, analysts say.

The landmark international agreement, whose objective is to prevent the spread of nuclear weapons and weapons technology, celebrates its 40th birthday on Tuesday.

Drafted for signature on July 1, 1968, the NPT is the most universal arms control treaty in force, and has so far been signed by a total of 190 countries.

Since it was put into effect on March 5, 1970, the NPT's main purposes have been generally accepted by the international community.

However, analysts, say the treaty is now in urgent need of an improvement to counter alleged proliferation in some countries.

NPT at risk

The five permanent members of the UN Security Council said in May that the NPT was under threat, calling for actions to shore up the treaty.

"The proliferation of nuclear weapons constitutes a threat to international peace and security," China, the United States, Britain, France and Russia said in a joint address on the final day of a two-week meeting of NPT member nations in Geneva.

"This ... imperils prospects for progress on other NPT goals such as nuclear disarmament and hurts prospects for expanding international (civil) nuclear cooperation," said British chief delegate John Duncan, speaking on behalf of the five countries.

They also expressed concern over Iran's nuclear issue.

"The proliferation risks presented by the Iranian nuclear program continue to be a matter of ongoing serious concern to us,"Duncan said.