The United States and South Korea have decided to extend military exercises in response to a recent spate of missile launches from North Korea, offering stern warnings for North Korean leader Kim Jong Un should he hold a nuclear test, officials announced Thursday. 

The decision to extend the Vigilant Storm joint military air drills comes after Pyongyang late Wednesday launched an intercontinental ballistic missile (ICBM), with additional missile launches early Thursday. South Korean officials say the ICBM failed while in flight, according to Yonhap news agency. 

The U.S.-South Korea war games, which began on Monday, had been scheduled to end on Friday and include some 240 fighter jets and other aircraft holding more than 1,600 flights. Officials did not say how long the drills would be extended.  

Defense Secretary Lloyd Austin, speaking to reporters following a meeting with South Korea Minister of National Defense Lee Jong-sup at the Pentagon, said the nations decided to extend Vigilant Storm “to further bolster our readiness and interoperability.” He added that the two will “continue to work closely together to develop options to protect the United States and our allies in the region.” 

And Lee threatened that should Kim use any use nuclear weapons against the South or other allies in the region such as Japan, it would “result in the end of Kim Jong Un regime by the overwhelming and decisive response of the Alliance.” 

The North Korean missile launches are the latest in a string of similar actions, including the firing of 23 missiles on Wednesday, including one that landed off the coast of South Korea for the first time, after testing several throughout the month of October.  

Washington and Seoul have condemned the launches, with the Biden administration pressing countries to enforce sanctions on Pyongyang for violating United Nations Security Council resolutions that ban the isolated nation from holding missile and nuclear tests. 

The most recent launches, which have prompted South Koreans to seek shelter, also follow a deadly Seoul crowd surge late last week that killed at least 153 people. 

“It’s highly unfortunate that [North Korea] has chosen to interrupt this solemn period with the illegal and destabilizing launch of an intercontinental ballistic missile last night as well as additional missile launches today,” Austin said.  

Asked whether the U.S. needs to adjust its strategy in response to an increasingly bellicose North Korea, Austin would only say that Washington will implement a larger U.S. military rotational presence in South Korea. 

“We don’t have a plan to change our permanent positioning or staging of assets on the [peninsula] currently,” he said. “But you’ll see assets move in and out on a routine basis.”

Lee and his delegation were in D.C. on Thursday for the 54th United States-Republic of Korea Security Consultative Meeting, where U.S. and South Korean officials reaffirmed previous military commitments and “concurred on the need to enhance combined exercises and training events to strengthen readiness against [North Korea’s] nuclear and missile threats,” according to a readout of the gathering.  

As part of the so-called war game enhancement, Austin and Lee pledged to conduct a table top military exercise annually, to include a scenario in which North Korea uses a nuclear weapon. 

And looking forward, the two “pledged to seek new measures to demonstrate Alliance’s determination and capabilities” in the face of Pyongyang’s threats.