Three former high-ranking US military officers have called for Britain to help defuse the crisis over Iran's nuclear program, saying military action against Teheran would be a disaster for the region. In a letter to the Sunday Times newspaper, the three former officers urged US President George W. Bush to open talks "without preconditions" with the Iranian government in a bid to find a diplomatic solution. The signatories were Lt.Gen. (ret.) Robert G. Gard, a senior military fellow at the Center for Arms Control and Nonproliferation in Washington; Marine Gen. (ret.) Joseph P. Hoar, former head of the US Central Command; and Vice Admiral (ret.) Jack Shanahan, former director of the Center for Defense Information. They said Britain "has a vital role to play in securing a renewed diplomatic push" and urged Prime Minister Tony Blair to make it clear he would oppose any military attack on Iran. The officers said an attack "would have disastrous consequences for security in the region, coalition forces in Iraq and would further exacerbate regional and global tensions." "The current crisis must be resolved through diplomacy," they said. Last week a respected think tank, the International Institute for Strategic Studies, said Iran was likely two to three years from having the capacity to build a nuclear weapon. The UN Security Council has imposed sanctions on Teheran, and threatened to impose more if it continues to refuse to roll back its nuclear program. Blair's office refused to comment on whether Blair would back military intervention and reiterated the prime minister's support for the UN's response. "Our position on Iran is clear; we think we need to pursue the route set out by the Security Council and Iran needs to respond to the demands of the international community and respond to demands of IAEA [International Atomic Energy Agency]," said a spokesman for Blair's Downing Street office. The US government has refused to rule out military action if Iran does not halt its nuclear activities, and has beefed up the US military presence in the Gulf. Bush also has vowed more aggressive moves against Iranian operatives in Iraq, where the United States accuses Iran of training and arming insurgents who attack US troops. In a separate letter, British Muslim, Jewish and Christian leaders called for a peaceful resolution to the crisis. Writing to The Independent on Sunday newspaper, Rabbi Tony Bayfield, head of reform Judaism in Britain; Lord Harries, the former Anglican Bishop of Oxford; and Imam Abduljalil Sajid of the Brighton Islamic Mission said there was "no justification in international law for attacking Iran militarily, and the use of force is not an option at this juncture." "There is still time to talk and we urge everyone to use it and pray for success," they said.