In view of North Korea's recent missile tests, the US government wants to increase the pressure on the leadership in Pyongyang.
A senior US government official said on Thursday (local time) in a telephone exchange with journalists that the two ballistic missile tests in late February and early March were a "serious escalation" by North Korea.
"These launches are a brazen violation of several UN Security Council resolutions." In response, the US Treasury Department will announce new sanctions against North Korea this Friday.
In addition, the US command for the Indo-Pacific region has ordered increased intelligence activities in the Yellow Sea - as well as increased readiness of the ballistic missile defense forces in the region.
"There will be a number of other measures in the coming days,"
North Korea recently caused unrest again with missile tests in the region.
According to its neighbors South Korea and Japan, the isolated country fired a ballistic missile towards the open sea in early March.
North Korea itself spoke of another important test in the development of an earth observation satellite.
According to information from Japan and South Korea, North Korea had already launched a suspected ballistic missile at the end of February and later spoke of a test for satellite development.
The US administration official said according to American findings, the tests involved a relatively new intercontinental ballistic missile system that North Korea is currently developing.
The tests would not have been full scale and full range, but would probably have served the purpose of testing parts of the new system before a full range launch followed at a later date.