South Korea and the United States said they fired eight surface-to-surface missiles early Monday off South Korea's east coast in response to North Korea's launch of a volley of short-range ballistic missiles on Sunday.

According to South Korea's Yonhap news agency, the action is a display of "the capability and readiness to carry out precision attacks" against the source of North Korea's missile launches or command and control centers.

President Yoon Suk-yeol of South Korea has promised to be harsher on North Korea, and agreed with U.S. President Joe Biden at a May summit in Seoul to improve joint military drills and their combined deterrence posture.

This year, North Korea has launched a flurry of missiles, Yoon said, and its missile and nuclear weapons programs have advanced to the point where they represent a threat to regional and global peace.

Yoon said at a memorial day event in South Korea that the South will continue to enhance fundamental and practical security features and prevent the North's nuclear and missile threats.

Yonhap reported that the South Korean and U.S. forces fired eight surface-to-surface missiles over a 10-minute period starting at 4:45 a.m. on Monday in response to the North's eight missiles fired on Sunday.

The South Korean Defense Ministry verified the firing of eight Army Tactical Missile Systems (ATACMS).

The practice comprised one U.S. Army missile and seven from South Korea, the U.S. Indo-Pacific Command said.

"The ROK-U.S. Alliance stays true to peace and prosperity on the Korean Peninsula and throughout the Indo-Pacific," it said in a statement.

North Korea's short-range ballistic missiles, launched into the sea off its east coast on Sunday, were likely the country's largest single test, and occurred only a day after South Korea and the U.S. halted joint military maneuvers.

For the first time in more than four years, the bilateral exercises between South Korea and the United States included an American aircraft carrier.

In retaliation to North Korea's latest missile tests, Japan and the U.S. held a joint military drill on Sunday.

Despite its rhetoric of diplomacy, North Korea, which is fighting its first known outbreak of COVID-19, has criticized prior joint drills as an indication of Washington's persistent "hostile tactics" toward Pyongyang.

Sunday's barrage was launched from four places, including Sunan in Pyongyang, according to Yonhap, which cited an unnamed source.