The United States is transporting 387 "bunker-buster" bombs to its air base on the island of Diego Garcia in the Indian Ocean as part of preparations for a possible strike against Iran's nuclear facilities, according to a report in Scotland's Sunday Herald.

The U.S. government signed a contract in January with Superior Maritime Services to transport 10 ammunition containers to Diego Garcia from Concord, California. The shipment includes 195 smart, guided Blu-110 bombs and 192 Blu-117 2,000lb bombs.

Both types of bombs could be used against reinforced or underground facilities.

Neither the United States nor Israel have ruled out military action if diplomacy fails to resolve the long-running row over Iran's disputed nuclear ambitions.

Contract details for the shipment were posted on an international tenders' website by the U.S. Navy.

"They are gearing up totally for the destruction of Iran," Dan Plesch, director of the Center for International Studies and Diplomacy at the University of London, told the Herald. "U.S. bombers are ready today to destroy 10,000 targets in Iran in a few hours."

Plesch is the co-author of a recent study on U.S. preparations for an attack on Iran.

The final decision on whether to launch an attack would be in the hands of U.S. President Barack Obama. Obama may decide it would be better for the U.S. to strike instead of Israel, Plesch said.

"The U.S. is not publicizing the scale of these preparations to deter Iran, tending to make confrontation more likely," he added. "The U.S....is using its forces as part of an overall strategy of shaping Iran's actions."

Diego Garcia is a British territory about 1,000 miles south of India and Sri Lanka. It is used as a U.S. military base as part of an agreement reached in 1971.

In the past, the British Defense Ministry has said that the U.S. would need permission to use Diego Garcia for offensive action. It has already been used in operations against Iraq during the 1991 and 2003 Gulf wars.

The U.S. Department of Defense did not respond to a request for a comment from the Sunday Herald.