SEOUL, South Korea — North Korea fired a possible submarine-launched ballistic missile off the East Coast Tuesday morning, according to the neighboring countries South Korea and Japan, marking the eighth missile test-fire this year alone.

“Our military detected a missile launch eastward from a site in the vicinity of Sinpo, South Hamgyong Province around 10:17 a.m.,” South Korea’s Joint Chief of Staff, General Won In-choul, told reporters.

The unidentified ballistic missile allegedly launched from a submarine and flew 370 miles at an altitude of 37 miles, according to South Korea’s military.

“It is likely a new mini-SLBM that North Korea showcased last week at an arms exhibition,” Shin Beom-chul, director of the Center for Diplomacy and Security at the Korea Research Institute for National Strategy, told ABC News.

Another analyst told ABC News that Kim Jong Un is developing submarine-launched ballistic missiles in order to prepare a more survivable nuclear deterrent able to blackmail his neighbors and the United States.

“North Korea cannot politically afford appearing to fall behind in a regional arms race with its southern neighbor,” Leif-Eric Easley, a professor of international studies at Ewha Womans University in Seoul, told ABC News.

Easley said that although the North Korean missile launch timing is largely driven by a technical schedule for when tests are ready and useful, there’s also a political factor.

“Pyongyang is celebrating the ruling party’s founding and looking to boost national morale after harsh pandemic lockdowns. And the Kim regime likely wants to one-up South Korean missile tests, at least in Pyongyang’s propaganda,” Easley said.

The same day, the intelligence chiefs of South Korea, the United States and Japan held a closed-door trilateral meeting in Seoul to discuss the pending issues in the Korean peninsula, such as the security situation, according to South Korea’s National Intelligence.

Meanwhile in Washington, South Korea’s chief nuclear envoy Noh Kyu-duk discussed North Korea’s missile launch over the phone with the U.S. Special Representative for North Korea Policy Sung Kim. Noh happened to be in Washington for the meeting to discuss ways to bring the North back to the negotiating table the day before.

North Korea’s missile launch comes only two weeks after Pyongyang made a conditional peace offer to Seoul on reconnecting the military hotline. For Seoul, it was a symbolic gesture that their relations could see an improvement.

As Pyongyang raised international concern by firing yet another missile just 19 days after the latest missile test, South Korea’s presidential office held a presidential National Security Council right after the missile launch.

“The council members expressed deep regret that North Korea’s launch occurred while active consultations are underway with related countries like the United States to advance the Korean Peninsula peace process,” South Korea’s Unification Ministry said in an official statement.

North Korea’s last test-fire of an SLBM was in October 2019.

ABC News’ Shihoo Lee contributed to this report.