The DPRK unsuccessfully fired an intercontinental ballistic missile (ICBM) as Pyongyang tested out more missiles on Thursday, according to the South Korean military.

Washington is calling for sanctions against Pyongyang, reinstating that along with Seoul, they will be extending the duration of their joint air drills, which is by far the largest military exercise of its kind between the two countries. 

In response, the DPRK condemned the exercises as "an irrevocable and awful mistake". 

Read next: 'Vigilant Storm'; largest US-S.Korea military drill yet against DPRK

Some populations in northern Japan were required to seek shelter during the launches. 

The largest of Thursday's launches, however, "is presumed to have ended in failure", the South Korean military said. 

"This action underscores the need for all countries to fully implement DPRK-related UN Security Council resolutions," US State Department spokesman Ned Price said.

Pak Jong Chon, secretary of the Central Committee of the Workers' Party of Korea, made a statement:

 "It was reported that the US and South Korea decided to extend the combined air drill Vigilant Storm. 
 
It is a very dangerous and false choice. 
 
The irresponsible decision of the US and South Korea is shoving the present situation caused by provocative military acts of the allied forces to an uncontrollable phase. 
 
The US and South Korea will get to know what an irrevocable and awful mistake they made."

Yesterday, the DPRK has issued a warning to the United States and South Korea against the pair continuing their joint military drills, vowing a more powerful response to US provocations. 

Earlier, Washington and Seoul kicked off their largest five-day-long joint aerial drills, named Vigilant Storm, with hundreds of warplanes performing simulatory attacks. 

According to the US Air Force, the wargames include 240 warplanes conducting 1,600 sorties. The US Air Force boasted that the exercises were unprecedented in their scale.