North Korea fired unidentified projectiles on Thursday, according to the South Korean military, less than a week after leader Kim Jong Un oversaw the test-firing of multiple rockets and missiles.

"We confirmed that North Korea fired two rounds of missiles towards (an) eastern direction from Northern Pyongan Province at 16:29 p.m. and 16:49 p.m. (local time). Estimated travel distances were 420 km, 270 km, respectively," a South Korean military official told NBC News. The Northern Pyongan Province is an area located to the west of the country.

The South Korean and U.S. authorities are conducting analysis for more detailed information and NBC News also said that the chief national security advisor in South Korea is monitoring the situation.

"(The) South Korea military has reinforced surveillance and vigilance for any more North Korean missile launches, and is maintaining fully preparedness by cooperating with the U.S.," the official added.

The suspected short-range missiles appear to have been launched from a location near a missile base in Sino-Ri, according to the Dow Jones news agency. This is about 130 miles north of the demilitarized zone.

The new launches come as the U.S. Special Representative for North Korea, Stephen Biegun, travels to Seoul to meet with officials and discuss denuclearization efforts.