The US today urged Pakistan not to expand its nuclear weapons programme today after a think tank claimed Islamabad was building a nuclear reactor able to fuel up to 50 atomic bombs a year.

Foreign ministers of the five permanent members of the UN Security Council and Germany plan to approve a package of incentives and penalties meant to reward Iran if it gives up uranium enrichment – and punish it if it doesn’t, diplomats said today.

US administration officials say they remain committed to a diplomatic solution to ensure Iran does not obtain nuclear weapons, but they will not rule out military action as an option, even as they try to calm down talk about military planning.

US PRESIDENT George W Bush and German Chancellor Angela Merkel criticised Iran’s decision to resume its nuclear programme, but clashed over Ms Merkel’s call to shut down the US prison camp at Guantanamo Bay, Cuba.

The UN atomic agency revealed today that Iran received black-market designs to encase weapons-grade uranium and diplomats said they appeared to be part of blueprints for a nuclear warhead.

Pressure is mounting on the United Nations nuclear agency to report Iran to the Security Council as it prepares for an emergency meeting today to ease a stand-off with the Tehran regime.

Sophisticated uranium-enrichment equipment, which could be used in the production of nuclear weapons, has been discovered by United Nations inspectors in Iran, US sources said today.

The key issue in the discovery of 11 warheads in an Iraqi bunker is whether they were intended to be filled with lethal chemical agents or explosives, former UN weapons inspectors said.