North Korea said Sunday that the United States is trying to bring "dark clouds of conflict and war" to the Korean Peninsula, criticizing Washington for imposing new unilateral sanctions on Pyongyang, official media reported.

The U.S. administration of President Donald Trump has ignored "our efforts" to develop inter-Korean relations and stabilize the peninsula, the Korean Central News Agency quoted a Foreign Ministry spokesman as saying in a statement.

On Friday, Washington imposed sanctions against 56 vessels, shipping companies and trade businesses linked to North Korea in what Trump called the "heaviest" sanctions ever imposed on the country.

Trump also warned that if the sanctions do not lead Pyongyang to move toward denuclearization, the United States may have to take a "very rough" step, signaling he does not rule out a military option in dealing with North Korea.

The spokesman said Trump "blatantly assaulted" North Korea with "abusive remarks," adding Pyongyang has nuclear weapons as a "precious sword of justice" to defend the nation against intimidation.