It's the latest in a series of missile launches by the North since South Korea and the US began annual military drills. This year's drills are the largest ever, and come after the North's nuclear test and long-range rocket launch earlier this year.

Monday's launch comes on the heels of one Friday, when North Korea launched two medium-range ballistic missiles into the Sea of Japan.

"The missiles were fired near the eastern coastal city of Hamhung, and analysts say the short-range projectiles traveled about 120 miles", Elise tells our Newscast unit.

North Korea has on Monday launched five short-range missiles into the sea off the east of the peninsula. Earlier Monday, Yonhap reported that the South Korean government had warned that North Korea was capable of conducting a fifth nuclear test at any time.

In recent weeks, Pyongyang has maintained a daily barrage of nuclear strike threats against both Seoul and Washington, ostensibly over continuing large-scale South Korea-US military drills that North Korea sees as provocative rehearsals for invasion.

North Korea has been trying to improve the range of its multi-rocket launchers as well as short-range ballistic missiles. Its resolutions ban North Korea from developing ballistic missiles out of concern that they could be used to carry nuclear bombs.

The website 38 North, which specializes in North Korean affairs and is run by the U.S.-Korea Institute at Johns Hopkins University's School of Advanced International Studies, said Friday that satellite imagery from March 6 and March 14 show active maintenance at the Punggye-ri nuclear test site.

APPHOTO LJM108: U.S. State Department's Special Representative for North Korea Policy Ambassador Sung Kim, right, answers a reporter's questions as Coordinator for Sanctions Policy Ambassador Daniel Fried, left, listens after finishing the high level sanctions meeting at the Foreign Ministry in Seoul, South Korea, Monday, March 21, 2016.

"If North Korea launches another provocation, we will counter it with our airborne firepower and end their will to start a war".