Republican Senator Roger Wicker believes America must consider all options, including nuclear attack.
The broadcast voice said six missiles were incoming within the next 15 to 25 minutes.
When and what will be discussed at the meeting had not been disclosed.
"As every day goes by, we are at greater risk of total annihilation," psychologist John Gartner said.
If he survives the initial blow, the president can enter a bunker and lead the nation from there.
The anti-missile system is part of the capital's Cold War-era line of defense, which has 68 nuclear tipped rockets ready to blast incoming strikes from the sky.
"It's not the language that plays on emotions of people—it's more of language that tends to ridicule the adversary," Loretta Napoleoni says.
"It's not going to be like toppling Hussein," the retired general said.
"I don't see the opportunities to solve this diplomatically at this particular point," Mullen said.
Missiles that F-35 stealth fighters already carry need only slight tweaks to be able to target ICBMs, an aerial combat expert says.
South Korea's dronebots will be operated by a team targeting North Korea's nuclear and missile sites.
China does not believe in the arms race, a military analyst said.
"We have a responsibility to plan for all hazards," emergency management administrator Vern Miyagi said.
Hawaii is refreshing its nuclear defense plan for the first time since 1985.