The threat comes amid heightened tensions on the Korean Peninsula — and increasingly bellicose rhetoric from the North — that have prompted the U.S. to increase the number of missile interceptors in Alaska, among other measures.
On Tuesday, as part of a joint U.S.-South Korean military exercise code-named “Key Resolve,” U.S. officials said a B-52 strategic bomber capable of carrying nuclear weapons flew over South Korea. On Wednesday, the U.S. Embassy in Seoul tweeted a photo of the bomber in the air.
North Korea’s state broadcaster issued the air raid alert at about 9:30 a.m. local time, telling civilians to take cover in bomb shelters and directing military units to undertake unspecified countermeasures in what appeared to be a simulcast with the military’s own cable-based broadcast network, analysts said.
The alert was lifted after one hour. Other state-controlled media outlets, such as the Korean Central News Agency and Chosun Central TV, did not report on the alert.
“This was the first use of the public radio system for broadcasting an air raid warning,” military intelligence analyst John McCreary said in an email to The Washington Times. “This was probably a no-notice drill in response to the U.S. announcement about B-52s operating over South Korea.”
Mr. McCreary said the alert was likely a test rather than a full-scale civil defense drill because it lasted only one hour, whereas a full-scale drill takes up to a full day in large cities.
“The use of a nationwide radio broadcast implies the North’s leaders expect they will need such a system at a time when people would be away from their homes … They expect the population to respond swiftly according to plan without advance warning. That is uncommonly realistic preparation,” Mr. McCreary said. “The B-52 announcement had effect.”
An anonymous officer at the South Korean Joint Chiefs of Staff told the Yonhap news agency that the alert was likely intended to underline for both the civilian population and the military that the country is engaged in an increasingly tense standoff.
The rhetorical temperature has been rising on both sides of the demilitarized zone that divides the two countries since the imposition earlier this month of tough new U.N. sanctions on North Korea in response to Pyongyang’s illegal nuclear test in February.
A few days after the U.N. acted, the Key Resolve exercise got under way. Although the U.S. and South Korea have stressed the drill is defensive in nature, Pyongyang has condemned it as a rehearsal for an invasion.
The 10-day joint exercise, the first to be planned and carried out under the command of South Korean rather than U.S. forces, ended Thursday and a senior U.S. military official said it had been a success.
“This is the first major exercise that [South Korea’s Joint Chiefs of Staff] has planned and conducted. We did everything we needed to do for training. The opportunity to get together was excellent,” Lt. Gen. John Johnson, the 8th Army Commander, told Yonhap.
In recent months, North Korea has said it has scrapped the cease-fire that ended fighting in the Korean War in 1953, and cut off a hotline to South Korea. The secretive regime also has threatened a “pre-emptive” nuclear attack on the United States and noted that the U.S. mainland is within reach of its rockets.