North Korea's military has fired over 100 artillery shells into the sea off the country's east coast in response to the firing of rocket launchers by South Korea in joint drills with the United States, South Korean military sources said Tuesday.

North Korea later said its army units on the eastern front fired 82 shells from multiple rocket launchers toward the sea for eight and a half hours as "counteraction and warning military action against the enemy's planned sinister provocation attempt," according to the official Korean Central News Agency.

The firing of several dozens of rounds in the morning, followed by more shots later in the day, from Kangwon Province comes after similar shelling by the North the previous day and further heightened border tensions as live-fire drills by the South Korean and U.S. militaries continue near the inter-Korean border.

A spokesman for the General Staff of the Korean People's Army said in a statement Tuesday, "The KPA seriously warns the enemy side once again to stop at once the irritating military actions in the area close to the front."

"Our military counteraction against the continued provocative actions of the enemies will be more offensive as the days go by," the spokesman said, according to the KCNA report.

The spokesman said South Korea's military fired multiple rocket launchers and howitzer guns at around 9:15 a.m. Tuesday, according to another KCNA report issued earlier in the day.

On Monday, South Korea's military said it detected about 130 artillery shells fired off North Korea's east and west coasts in violation of a 2018 inter-Korean agreement designed to reduce border tensions.

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