Washington ? President George W. Bush rejected a plea from Israel last year to help it raid Iran’s main nuclear complex, opting instead to authorize a new U.S. covert action aimed at sabotaging Iran’s suspected nuclear weapons program, The New York Times reported.

Israel’s request was for specialized bunker-busting bombs that it wanted for an attack that tentatively involved flying over Iraq to reach Iran’s major nuclear complex at Natanz, where the country’s only known uranium enrichment plant is located, the Times reported Saturday in its online edition. The White House deflected requests for the bombs and flyover but said it would improve intelligence-sharing with Israel on covert U.S. efforts to sabotage Iran’s nuclear program.

The covert efforts, which began in early 2008, involved plans to penetrate Iran’s nuclear supply chain abroad and undermine electrical systems and other networks on which Iran relies, the Times said, citing interviews with current and former U.S. officials, outside experts and international nuclear inspectors who spoke on condition of anonymity. The covert program will be handed off to President-elect Barack Obama, who will decide whether to continue it.