U.S. lawmakers have approved a Pentagon request for more than $81 million in funding to make improvements to a massive bomb designed to penetrate deeply-buried enemy facilities.
News reports say defense appropriators in Congress agreed to the request earlier this week, a month after Iran announced it would begin uranium enrichment at its underground Fordow facility, which is beneath a mountain near the Shi'ite holy city of Qom. Pentagon officials have described the request as "urgent" and say the money is needed to fix issues identified in initial testing.
Some observers believe the bomb is designed for a possible attack on Iranian facilities, but officials will not directly make that connection.
The weapon is officially called the Massive Ordnance Penetrator, but is known informally as a "bunker-buster" bomb. It weighs more than 13 metric tons - so heavy that only one can be carried on the most capable U.S. bomber aircraft. The bomb is said to be designed to penetrate up to 60 meters of rock or concrete before exploding. The Wall Street Journal reports that the $81 million in improvements will allow the bomb to penetrate greater depths.
The U.S. Air Force worked on the weapon with the Boeing company, and the U.S. has so far invested in developing about 20 of them.
President Barack Obama said in his State of the Union address last month that the United States is determined to prevent Iran from getting a nuclear weapon. He said he will take no options off the table to achieve that goal.
Iran denies it is working to develop nuclear weapons, and says its nuclear activities are peaceful.