Iran's nuclear ambitions are unclear - its government insists scientists are enriching uranium for a power plant, while the US and European nations believe the aim is to produce atomic weapons. Whatever the truth, tensions have risen to a dangerous level and diplomacy is of the highest priority. The US, which has not had diplomatic relations with Iran since 1980, is driving the anti-Tehran rhetoric, claiming President Mahmoud Ahmadinejad's government is supporting terrorism, flouting international law and trying to conceal its nuclear activities. That these are the same reasons given for the US-led invasion of Iraq three years ago to oust president Saddam Hussein is worrying; the terrorism link has never been proven, nor have the biological, chemical or nuclear weapons been found. Nonetheless, officials of President George W. Bush's administration have frequently repeated these charges, always leaving on the table the possibility that Hussein's fate could also be that of Mr Ahmadinejad. Iran has responded to the allegations with equal hostility, last week taking its most aggressive step by embarking on a week of war games involving thousands of troops and the testing of missiles and torpedoes. The manoeuvres came days after the United Nations Security Council demanded that Tehran suspend all uranium enrichment and asked the UN nuclear watchdog, the International Atomic Energy Agency, to report back in 30 days on whether Iran had complied. Negotiations over Iran's nuclear programme have repeatedly faltered over the government's insistence that as it has signed the global nuclear safeguards pact, the Non-Proliferation Treaty, it is entitled to enrich uranium for electricity production. Suggestions that the ore be enriched outside Iran have been rejected - hardening suspicions that it wants to arm itself with nuclear weapons against its rival Israel, believed by experts to have between 100 and 200 atomic bombs. That the US is sending mixed signals does not help: Last month it signed a deal with India giving it access to American civil nuclear technology. International rules do not permit such agreements because India has not signed the Non-Proliferation Treaty. The US was wrong to make such a deal and Congress may yet reject it. Negotiations with Iran may be stalled, but there is hope: upcoming talks between Washington and Tehran over Iraq. The issue may not be on the agenda, but it has to be introduced to discussions to avert a rapidly escalating crisis. Nuclear proliferation cannot be tolerated and all nations should strive to destroy their weapons stockpiles. Iran should be permitted the nuclear-produced electricity it craves, but its government must also comply with the international regulations in place to guard against arms proliferation.