The United States has called on countries to sever diplomatic and financial ties with Pyongyang and suspend the flow of North Korean guest workers.

:: Kuwaiti authorities have begun taking measures against North Korea, including stopping direct flights to and from Pyongyang, state news agency KUNA cited an official source in Kuwait’s foreign ministry as saying on Thursday.

The official source said the measures included stopping entrance visas for North Korean workers and stopping the issuance of commercial licenses.

Kuwait’s measures come as U.S. President Donald Trump ratcheted up his rhetoric toward North Korea on Thursday.

Trump said North Korea should be “very, very nervous” if it even thinks about attacking the United States or its allies, after Pyongyang said it was making plans to fire missiles over Japan to land near the U.S. Pacific territory of Guam.

The United Nations Security Council imposed new sanctions on North Korea on Saturday that could slash by a third the Asian state’s $3 billion annual export revenue over Pyongyang’s two intercontinental ballistic missile tests in July.

The Kuwait foreign ministry said it was committed to implementing Security Council resolutions on North Korea.

It also said it had stopped financial transactions and loans to North Korea, banned all North Korean imports and decreased the numbers of North Korean diplomats in the country.

The United States has called on countries to sever diplomatic and financial ties with Pyongyang and suspend the flow of North Korean guest workers, as well as impose bans on North Korean imports.