The United States has diverted a shipment of bunker-busters designated for Israel.

Officials said the U.S. military was ordered to divert a shipment of smart bunker-buster bombs from Israel to a military base in Diego Garcia. They said the shipment of 387 smart munitions had been slated to join pre-positioned U.S. military equipment in Israel Air Force bases.

"This was a political decision," an official said.

In 2008, the United States approved an Israeli request for bunker-busters capable of destroying underground facilities, including Iranian nuclear weapons sites. Officials said delivery of the weapons was held up by the administration of President Barack Obama.

Since taking office, Obama has refused to approve any major Israeli requests for U.S. weapons platforms or advanced systems. Officials said this included proposed Israeli procurement of AH-64D Apache attack helicopters, refueling systems, advanced munitions and data on a stealth variant of the F-15E.

"All signs indicate that this will continue in 2010," a congressional source familiar with the Israeli military requests said. "This is really an embargo, but nobody talks about it publicly."