North Korea fires two missiles as a US carrier begins drills with South Korean warships

North Korea tested two more missiles on Monday, hours before the US nuclear-powered aircraft carrier USS Nimitz began joint military exercises with South Korean warships.

Tensions on the Korean peninsula ran high as the US struggled to build its relationship with South Korea and as North Korea protested the military drills, showing its own nuclear force in response.

The last two missile fires mark North Korea’s seventh missile test this month.

The South Korean military said the two short-range ballistic missiles were launched from a western landlocked area south of the North Korean capital Pyongyang and flew over 200 miles. Japan’s military said the missiles took an erratic trajectory.

“North Korea seriously threatens the Korean Peninsula and regional security order with multiple launches of ballistic missiles, including ICBMs, and the impact of their offensive use of nuclear weapons through their self-proclaimed ‘nuclear tactical counterattack training,'” South Korea’s Joint Chiefs of Staff Gen. Seung-kyum Kim said in a statement Statement after visiting the USS Nimitz.

The South Korea-US alliance “will respond resolutely and overwhelmingly to any enemy provocation and aggression” and “profoundly clarify the following fact: any attempt at enemy nuclear attack will surely mean the end of their regime,” Kim said.

Last week, North Korea said it used a ballistic missile launch to simulate a nuclear attack on South Korea.

The US has increased its presence in the region, while China is becoming friendlier to Russia and more resentful of the self-governing island of Taiwan that Beijing claims as its own.

The Associated Press contributed to this report.