The Pentagon has acknowledged that it is speeding up plans to deploy a massive bomb capable of knocking out deeply buried enemy facilities. The giant "bunker buster" is believed to add fighting power to the U.S. arsenal against Iran's nuclear program, defense experts argue. U.S. officials, however, have refused to confirm the connection. The 30,000-pound massive ordnance penetrator is capable of penetrating up to 60 meters of earth, or a thick layer of concrete, before exploding. It weighs more than 13 metric tons, allowing just one such bunker buster to be carried by U.S. bomber aircraft. "It is under development...