The US Defense Department on Monday said it wants to speed up production plans for an enormous "bunker buster" bomb amid concern over underground nuclear sites in Iran and North Korea.
The Pentagon has asked Congress for extra money to ensure the massive ordnance penetrator (MOP) would be ready by July 2010, spokesman Bryan Whitman told reporters.
"The department has asked for reprogramming of about 68 million dollars to start production for some of these in 2009," Whitman said.
"This will help it accelerate some if it's approved."
The bomb, weighing in at 30,000 pounds and carrying 5,300 pounds of explosives, would be delivered by Northrup Grumman's B-2 aircraft.
The MOP is seen as a potential weapon against nuclear facilities in Iran and North Korea that are mostly buried underground. Washington has demanded that both countries abandon their nuclear programs and refused to rule out possible military action.
Whitman declined to say whether the move was designed to prepare for a possible strike against Iran, saying the Pentagon since 2004 had been looking at developing weapons "that would allow us to go after more hardened, more deeply buried targets."
He mentioned that Pyongyang has sought to conceal its nuclear activities. "One of the ways you hide is by going underground" and fortifying sites, he said.
Boeing builds the MOP, which could become the biggest conventional bomb ever used by the US military.