Iran warns Israel not to attack its nuclear facilities The Iranian president, Mahmoud Ahmadinejad, right, visits a nuclear reactor in Tehran. Photograph: Presidential offical website/handout/EPA Iran has warned Israel against mounting an attack on its nuclear facilities amid rising international tension over its uranium enrichment programme. General Ahmad Vahidi issued a statement warning Israel that an attack would lead to the collapse of the Jewish state. The warning came after a UN report said Iran had tripled its production rate of enriched uranium over the past three months. The confidential report to member states, seen by the Guardian, also states that Iran is refusing to co-operate with an investigation into evidence that the country may have worked on designing a bomb. Vahidi's remarks were posted on the state-run Press TV's website amid increasingly tough rhetoric from Israel warning of the need to halt Iran's nuclear development. Israeli officials say Israel must act by the summer because Tehran is moving more of its nuclear installations underground. The UN report states that the International Atomic Energy Agency (IAEA) found that much of the increased production of uranium, enriched to the level of 20%, had taken place at an underground site known as Fordow. Tehran says it needs the material for its research reactor, which produces medical isotopes, but western governments argue that its stock of enriched uranium brings it significantly closer to weapons-grade fissile material. The IAEA inspectors also found that Iran had stepped up the installation of centrifuges at its main uranium enrichment plant in Natanz. Over the past three months, 2,600 new centrifuges have been brought into operation, spinning uranium gas. The report found that Iran had now produced nearly five and a half metric tonnes of low enriched uranium - enriched to about 3.5% - and about 109kg of uranium enriched to 20%. If enriched further, to more than 90% purity, the total stockpile would be more than enough to make four nuclear warheads. Iran says it has no intention of making weapons, and the report may not be enough for western countries, led by the US, the UK and France, to persuade Russia and China to take part in an escalation of sanctions. The Russian prime minister, Vladimir Putin, said the focus on the nuclear programme was a cover for western attempts to oust the clerical regime in Tehran.