North Korea's leader, Kim Jong Un, addresses the Supreme People's Assembly, North Korea's parliament, in Pyongyang, North Korea, September 8, 2022.
Seoul, South Korea CNN  — 

North Korea launched two short-range ballistic missiles into the waters off the east coast of the Korean Peninsula on Monday morning, South Korean authorities said, the latest in series of missile firings as South Korean and United States forces engage in their largest military exercises since 2017.

Japanese authorities said the two missiles are suspected of having flown on “an irregular trajectory,” with a maximum altitude of 50 kilometers (31 miles) and at a distance of of 350 kilometers (217 miles).

Irregular trajectories could mean the missiles are maneuverable, in contrast to regular ballistic missiles, which travel in an arc.

The missile launches come as South Korean and US forces engage in large-scale military exercises involving thousands of troops on the southern part of the Korean Peninsula.

Following Monday’s missile launch, the South Korean military said it would continue operating the Warrior Shield field training exercise at high intensity until they end in early April.

Two large US Navy platforms, the aircraft carrier USS Nimitz and the amphibious assault ship USS Makin Island are near the southern coast of South Korea preparing to participate in exercises later this week.

North Korean missile launches tend to spike when Washington and Seoul hold joint military drills.

The latest US-South Korea exercises are among the largest the two allies have put on since they scaled back such military displays in 2017, when then-US President Donald Trump tried to offer an opening for North Korea to negotiate an end to its long-range missile and nuclear weapons programs.

That opening has long since closed, with North Korea last year conducting a record number of missile tests while pledging to develop its nuclear program to arm the missiles.

The North’s missile testing has picked up again in recent weeks, as tensions on the Korean Peninsula continue to escalate.