The United States and South Korea have criticized another round of North Korean short range missile launches, saying two more missiles were fired Monday.

U.S. State Department spokeswoman Jen Psaki Monday said the launches violate several U.N. resolutions.

"These resolutions require North Korea to abandon its ballistic missile program in a complete, verifiable and irreversible manner. So we urge North Korea to exercise restraint and take steps to improve relations with its neighbors. The onus is on North Korea to refrain from provocations."

South Korean Defense Ministry Spokesman Kim Min-seok said the suspected Scud missiles traveled about 500 kilometers before falling into the Sea of Japan.

"This launch of short-range ballistic missiles was made without prior notice by surprise, and it was an abnormal military move. North Korea is doing an act of double standard by taking a peace offensive ostensibly, but later launching reckless provocative acts. We strongly call for an immediate stop."

[[North Korea conducted four similar missile launches on Thursday last week.

Pyongyang has not commented on the latest launches, which come as Seoul and Washington conduct large-scale joint military exercises. The North views the drills as an unacceptable provocation.