Donald Trump said on Tuesday that the us would take military options against north Korea "if forced to do so" and called on global leaders to unite to cut off Pyongyang's economic lifeline.

"We are fully prepared for the second option.

The so-called military option.

If we have to, we will, "the President warned.

"He's saying something that should never be said," trump added, referring to Kim Jong Un, the north Korean leader. "we're responding to these things."

Mr Trump's comments came as the us took additional unilateral sanctions against eight north Korean Banks and 26 individuals.

"This further advances our strategy of completely isolating north Korea to achieve our overall goal: a peaceful and denuclearization Korean peninsula," he said.

"All countries now have to act to ensure that the north Korean regime completely renounce," Mr Trump said after the sanctions were announced.

He also thanked Spain and China, which expelled the north Korean ambassador, who cut off all bank contacts with north Korea.

Mr Trump called the move "unthinkable" in the past.

Two of the sanctioned north koreans work in dubai's Banks, suggesting that north Korea's overseas financial network remains active, even as the us takes the lead in cracking down on north Korea's overseas operations.

In accordance with the information provided by the us Treasury, was in the sanctions list Kwak Chong - chol, is north Korea a front companies, general manager of the company responsible for labor export to north Korea to collect money, while Ryom Hui - bong to take cash from dubai to Pyongyang.

Others on the list work in places like Moscow and Beijing.

North Korea has tens of thousands of labor export workers, who repatriate about $500 million in hard currency each year.

About 50,000 north koreans work in China and 20,000 in Russia.