The United States will lead a mock attack on a nuclear facility in response to a provocative nuclear test by North Korea in the last one month.

A South Korean Defense Department told CNN that the simulation, dubbed joint exercise “Red Flag,” will take place in Alaska from Oct. 3 to Oct. 21.

The official said the drills to be conducted alongside South Korea, are not aimed particularly at North Korea following claim by the North that it successfully tested a nuclear warhead.

The nuclear test conducted two weeks ago by North Korea is the second this year and the fifth one ever.

The U.S. and South Korea will also simulate what to do in the event of a sudden missile attack.

North Korea’s nuclear test prompted a strong rebuke from the international community, with South Korea saying it was “getting ready for the worst case scenario.”

In its reaction, North Korean state media called the South “puppet warmongerers” when reporting the upcoming military drills.

South Korea, however, said the nuclear facility attack simulation will take place using a GBU-31 Joint Direct Attack Munition, a kit that converts bombs that normally just free-fall from planes into guided munitions.

A GBU-31(V)3/B 2,000 lb penetrator is loaded into the weapons bay of a USAF B-1B during combat operations over Iraq in 2003.

The weapon system made its debut during NATO’s air campaign in the Kosovo conflict and was most recently used in NATO’s 2011 Libya campaign, according to the U.S. Air Force.

The U.S. on Wednesday also announced that it conducted its second show of force operation in two weeks in South Korea to send North Korea a message.

It sent two B-1B bombers to fly alongside the Korean demilitarised zone, a source told CNN.

“The bond between the United States and the Republic of Korea is ironclad and the strength of that commitment will not be shaken by North Korea’s aggressive behaviour,” said Lt. Gen. Thomas W. Bergeson, 7th Air Force commander.

“What we are showing today is just one tool we have to choose from a wide array of options,” Bergeson said.

The U.S. flew B-1 bombers over Seoul on Sept. 13 in a show of force responding to the recent North Korean nuclear test.

A day after that flyover, North Korea accused the U.S. of “bluffing” and “blustering” with the flyover and said such actions were inflaming tensions on the Korean Peninsula.