The United States Air Force has received the delivery of the first batch of a massive 30,000 pound bunker-buster bomb dubbed as the Massive Ordnance Penetrator (MOP).

This precision-guided bomb is reportedly larger than the presently available deep penetrating bunker buster - the 5000 pound GBU-28.

The delivery was made by the aerospace and defense giant, Boeing Co., which received a $32 million contract in August, 2011, for supplying eight of the munitions.

According to the Los Angeles Times, the military has developed and ordered 20 of the GPS-guided bombs at a total cost of about $314 million. They are designed to be dropped on targets by the Boeing-made B-52 Stratofortress long-range bomber or Northrop Grumman Corp.'s B-2 stealth bomber.

The new purchase by the Air Force signifies new defense policies by the Pentagon, and the MOP is viewed as a weapon for going after underground bunkers and tunnels in North Korea or Iran.

The AFP reported that the United States, which suspects Iran and North Korea have built nuclear facilities deep underground to thwart any possible air raids, has been developing the MOP bomb since about 2007.

The initial explosive test of MOP took place on March 14, 2007, in a tunnel belonging to the Defense Threat Reduction Agency (DTRA) at the White Sands Missile Range, New Mexico. This is the same place where the first atomic bomb testing was conducted during World War II.

Although models and illustrations of the MOP have been displayed, there are no photo releases. The Pentagon hasn't even permitted Boeing to comment on the defense contract, citing national security concerns.

However, the LA Times mentioned that Boeing's past news releases and publicly disclosed Air Force contract announcements indicated that the development of the massive bunker-buster bombs took place at its Phantom Works facilities in St. Louis.