North Korea on Tuesday threatened to carry out more weapons tests after its fourth pair of projectiles in less than two weeks following the start of joint exercises between the US and the South.

The statement comes just an hour after North Korea fired “two projectiles that were assumed to be short-range ballistic missiles” from South Hwanghae province on its west coast.

The missiles flew about 450 km across the peninsula and into the East Sea, also known as the Sea of Japan, reaching an altitude of 37km and a speed of “at least Mach 6.9”, South Korea’s Joint Chiefs of Staff (JCS) said in a statement.

Pyongyang has always been infuriated by military exercises between the South and the US, seeing them as rehearsals for invasion, but in the past, it has tended to avoid carrying out missile tests while the war games were taking place.

According to officials, all joints drills between the South and the US were “aggressive war exercises simulating the surprise and preemptive attack on the DPRK”.

Although the UNSC has banned North Korea from ballistic missile launches resolutions, and despite a meeting between North Korean leader Kim Jong Un and US President Donald Trump last month, there has been no change in their stance.

Last week, US President Donald Trump had underlined his personal support for North Korean leader Kim Jong-un, even as he admitted that Pyongyang’s recent missile tests “may” violate the UN resolution.

Trump said in a series of tweets, “There may be a United Nations violation, but Chairman Kim does not want to disappoint me with a violation of trust, there is far too much for North Korea to gain”.

“Chairman Kim has a great and beautiful vision for his country, and only the United States, with me as President, can make that vision come true”.

“North Korea’s attempt to upgrade its missile capabilities is a serious problem, not only to our country alone but to the entire region and we’ll be thorough in surveillance and steadily develop a comprehensive missile defence system,” he added.

The latest launch came after the South Korean and US militaries began mainly computer-simulated joint exercises on Monday to test Seoul’s ability to take operational control in wartime.