A central issue in the debate over the resolution, sponsored by the United States and Britain, is the veto power held by the council's five permanent members: Britain, China, France, Russia and the US.

All are nuclear powers which could use their vetoes to exempt themselves from legal obligations that the resolution would impose on other nations.

The US and Britain put forward the draft in March in an effort to keep WMD out of the hands of terrorists or "non-state actors" who are not addressed under existing non-proliferation treaties.

"Pakistan is not opposing the resolution," spokesman Masood Khan told a weekly news briefing.

"We have certain questions and concerns and we are trying to address in consultation with all members of the (UN) Security Council.

"These concerns range from the application of chapter seven, to the creation of a committee as a follow-up mechanism, to the definition of non-state actors and so on."

However, he added that Islamabad supported the draft's "general thrust".

"We are constructively engaging with all principal actors and Pakistan is against proliferation and we would like to cooperate in the this process."

Pakistan is among several non-permanent members of the security council who have raised concerns and are taking time to evaluate the draft.

The US proposal would effectively make it illegal for WMD and any related technology to be developed by or transferred to non-state actors, a term which some council members said needed a more precise definition.

An analysis by Pakistan's mission at the UN said the resolution left "many legal and technical loopholes open and ... creates potential problems about where, when and how its provisions would be applied or implemented".

Pakistan, like its nuclear rival India, is not a signatory to nuclear non-proliferation treaties.

Its chief nuclear scientist Abdul Qadeer Khan was found to be at the centre of the world's worst nuclear proliferation scandal in a UN probe late last year, and in February confessed to selling nuclear secrets to Iran, Libya and North Korea.

He was pardoned by Pakistan's President Pervez Musharraf.

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