North Korea on Tuesday hit out at the USA seizure of one of its cargo vessels, accusing Washington of defying the "underlying spirit" of their new diplomatic relationship and trying to bring Pyongyang to its knees.
The North Korean foreign ministry said in a statement that it rejected the United Nations security resolutions against their country, which the US used as reasoning to take control of the ship and demanded a return of the vessel.
The announcement of the U.S. seizure of the vessel came as tensions rose over Pyongyang's test launches of short-range missiles last week.
The foreign ministry statement rejected UN Security Council resolutions against North Korea, which the USA cited in impounding the vessel, as a violation of its sovereignty.
USA officials have stressed that the seizure announcement had nothing to do with the tests.
"The U.S. should carefully deliberate what consequences will follow in the current situation derived by their robbery and promptly return our ship", the Tuesday statement read. The case marked the first time the United States had seized a North Korean cargo vessel for allegedly violating sanctions.
North Korea's formal name is the Democratic People's Republic of Korea (DPRK).
Last week, the US Department of Justice said that the United States seized a vessel, known as Wise Honest, due to what it described as the breach of US and UN sanctions by engaging in illicit coal shipments.
US officials have shrugged off the three short-range missile tests, saying the door remains open for talks with the North.
A second summit between North Korean leader Kim Jong-un and US President Donald Trump ended without agreement in February, with the US insisting North Korea give up its nuclear programme and Pyongyang demanding sanctions relief.
The cargo ship arrived in American Samoa on Monday.
Under a series of USA and United Nations sanctions, North Korea is prohibited from a broad range of economic activities, including exports of materials such as coal.