North Korea has launched at least three unidentified projectiles

(CNN) — North Korea fired at least three unidentified projectiles Monday, according to US and South Korean officials.

“Our military detected 3 unidentified projectiles fired this morning from the Sondok area in Hamgyong Province, North Korea, toward northeast, toward the East Sea,” the South Korea Defense Ministry said in a text to reporters.

“Currently, our military is monitoring related movement in case of additional launch and is maintaining preparedness.”

The East Sea is also known as the Sea of Japan.

A US official told CNN that North Korea fired four unidentified projectiles.

Two other US officials said the launch was not unexpected. One of the officials said “signs” had been observed but didn’t say what they were.

“We are aware of a North Korean missile launch this morning into the East Sea, will continue to monitor the situation and are consulting closely with our South Korean and Japanese allies,” United States Forces Korea said in a statement.

No other details were immediately available.

The launch comes after last week’s firing of two unidentified short-range projectiles from an area near the coastal city of Wonsan into waters between the Korean Peninsula and Japan.

Those projectiles were likely part of North Korea’s military drills for its wintertime exercise, the Joint Chiefs of Staff said.

Last year, North Korea test-launched missiles 13 times amid stalled denuclearization talks with the United States.

In its New Year’s Day message, Pyongyang warned it will show off a “new strategic weapon” in the near future.

Experts said the “strategic weapon” may mean an advanced type of its intercontinental ballistic missile (ICBM) or a submarine-launched ballistic missile (SLBM).

This is a developing story. More to come.