The United States and South Korea are set to begin regular military drills on Monday amid fears that North Korea may launch what it calls an intercontinental ballistic missile, or ICBM.

The Ulchi Freedom Shield exercise will play out in South Korea through August 31, featuring drills to deal with emergencies on the Korean Peninsula.

The US and South Korean militaries say they will conduct the drills while considering North Korea's nuclear and missile programs as well as the shifting security environment amid Russia's invasion of Ukraine.

South Korea's Yonhap News Agency quotes an official of the country's Joint Chiefs of Staff as saying the exercise will involve about 30 field training events, compared to 13 in last year's edition.

Yonhap adds that at least one US B-1 bomber may also be deployed during the exercise. North Korea is on high alert for the aircraft.

Pyongyang's state-run Korean Central Television reported earlier this month that the country's leader Kim Jong Un had signed a written order on important military measures.

The media outlet reported he had called for stepping up the military's war preparations in an "offensive" way and also demanded practical drills.

A South Korean lawmaker said Seoul's National Intelligence Service told a closed-door meeting of a parliamentary committee on Thursday that Pyongyang could be preparing to carry out provocative military actions, including an ICBM launch, during the South Korea-US exercise.