WASHINGTON, June 10: The world's eight leading economic powers issued a policy statement on Thursday aiming to block the spread of nuclear weapons. The statement is particularly critical of the states that believed to posses clandestine nuclear programmes but leaves out self-declared nuclear states.

The statement, issued at the G8 meeting in Georgia, signals out two countries - Iran and North Korea - for chastisement for having nuclear ambitions. Three other states that are widely believed to possess atomic weapons but are not yet accepted as nuclear states - India, Pakistan and Israel, escape criticism.

But there are several indirect references to the discovery of a proliferation network, headed allegedly by Dr A.Q. Khan. The G8 leaders said they were "deeply concerned" about Iran's lack of compliance with the requirements of the UN nuclear watchdog, the International Atomic Energy Agency, and urged a complete dismantlement of North Korea's nuclear programmes.

They said that the history of the North's missile proliferation has also been a serious concern for all. The measures they announced aim to curb transfers of nuclear technology; enhance the IAEA powers, and step up abilities to prevent and respond to biological weapons attacks.

Some of these measures seem to have been directly influenced by the discovery earlier this year that a private network sold nuclear secrets and equipment to countries like Iran, Libya and North Korea.

To prevent further proliferation, the G8 leaders vowed to set international rules restricting access to uranium enrichment and reprocessing technology in a year. They also proposed to further tighten the existing restrictions on the transfer of nuclear technology.

A proposed freeze of one-year on transfer of nuclear technology will remain in place until the next G8 summit, which will take place in Britain, where the participants hope to enforce more permanent controls.

The leaders said they will work to "defeat proliferation networks" by stopping illicit financial flows and shutting down illicit plants, laboratories, and brokers, in accordance with national legal authorities and legislation and consistent with international law.

"Several of us are already developing mechanisms to deny access to our ports and airports for companies and impose visa bans on individuals involved in illicit trade," the leaders said.

They endorsed UN Security Council Resolution 1540 which calls on all states to "establish effective national export controls, to adopt and enforce effective laws to criminalize proliferation, to take cooperative action to prevent non-state actors from acquiring weapons of mass destruction, and to end illicit trafficking in such weapons, their means of delivery, and related materials."

The G8 leaders also noted that some countries "seek uranium enrichment and plutonium reprocessing capabilities for weapons programmes contrary to their commitments under the Treaty on the Non-Proliferation of Nuclear Weapons. "We reaffirm our commitment to the NPT ... and we will work to prevent the illicit diversion of nuclear materials and technology," the statement said.

The leaders also sought "universal adherence" to IAEA comprehensive safeguards and supported the suspension of "nuclear fuel cycle cooperation" with states that violate their nuclear nonproliferation and safeguards obligations.

The Proliferation Security Initiative received a strong endorsement from the G8 leaders. The initiative, which they call a "global response to a global problem," is designed to identify and stop the trafficking of weapons of mass destruction, their delivery systems, and related materials.

Leaders at the annual G8 summit from the US, Britain, Russia, Japan, France, Germany, Italy and Canada also announced plans to tighten up airline security. The 28-point plan includes an assessment of the threat of surface-to-air missiles posed to aircraft using airports in the G8 countries.