By KIM TONG-HYUNG and HYUNG-JIN KIM, Associated Press

SEOUL, South Korea (AP) — North Korea fired several ballistic missiles into the sea Monday, South Korea’s military said, hours after South Korean and U.S. troops kicked off their large annual combined drills, which the North views as an invasion rehearsal.

South Korea’s Joint Chiefs of Staff said the missile firings, North Korea’s fifth missile launch event this year, were detected from the North’s southwestern Hwanghae province. It called the weapons close-range but didn’t say how far they flew. The military said South Korea bolstered its surveillance posture and is closely coordinating with the United States.

Earlier Monday, the South Korean and U.S. militaries began their annual Freedom Shield command post exercise, their first major combined training of President Donald Trump’s second term. The allies have already been engaging in diverse field training exercises in connection with the Freedom Shield training.

North Korea’s Foreign Ministry warned Monday the latest training risks triggering “physical conflict” on the Korean Peninsula. It called the drills an “aggressive and confrontational war rehearsal” and reiterated leader Kim Jong Un’s stated goals for a “radical growth” of his nuclear force to counter what he claims as growing threats posed by the U.S. and its Asian allies.

This year’s training came after the South Korean and U.S. militaries paused live-fire training while Seoul investigates how its fighter jets mistakenly bombed a civilian area during a warm-up drill last week.

About 30 people were injured, two of them seriously, when two South Korean KF-16 fighter jets mistakenly fired eight MK-82 bombs on a civilian area in Pocheon, a town near the North Korean border, on Thursday. The bombing occurred while South Korean and U.S. forces were engaging in a live-fire drill ahead of the Freedom Shield exercise.

The initial assessment from the South Korean air force was that one of the KF-16 pilots entered the wrong coordinates and failed to visually verify the target before proceeding with the bombing. The second pilot had the correct coordinates but focused only on maintaining flight formation and dropped the bombs on the first pilot’s instructions without recognizing the target was wrong, according to the content of the latest briefing provided to The Associated Press.

Gen. Lee Youngsu, chief of staff of the South Korean air force, bowed and apologized Monday over the injuries and property damage caused by the bombing, which he said “should have never happened and must never happen again.”

Both the South Korean and U.S. militaries have halted all live-fire exercises in South Korea following the mistake. South Korean military officials say live-fire training will resume after they complete the investigation of the bombing and form preventative steps.

The South Korean air force earlier suspended the training flights of all its planes too but lifted the steps on Monday, except aircraft affiliated with the unit the two KF-16s belong to.