North Korea fired a suspected submarine-launched ballistic missile (SLBM) off its east coast, South Korea's military confirmed Tuesday.

Both the South and Japan said that at least one ballistic missile was launched — the latest in a series of weapons tests in recent weeks.

"Our military detected one unidentified short-range ballistic missile presumed to be an SLBM fired by North Korea," Seoul's Joint Chiefs of Staff said in a statement.

The South Korean military was "closely monitoring the situation and maintaining readiness posture in close cooperation with the United States, to prepare for possible additional launches."

Japanese Prime Minister Fumio Kishida said their initial analysis suggested that the North fired two ballistic missiles, and called the continued weapons tests "very regrettable."

The prime minister, who is going into a general election later this month, was pulled off the campaign trail to deal with the situation.

The US Indo-Pacific Command described the move as "destabilizing" but said it did not pose an immediate threat to the United States or its allies.