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, 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 retired Lt. -Gen. Robert G. Gard, a senior military fellow at the Center for Arms Control and Nonproliferation in Washington, DC; retired Marine Gen. Joseph P. Hoar, former head of US Central Command; and Vice Admiral 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.