President Donald Trump expressed disappointment with China on Thursday over the decision to allow oil into North Korea. He was “very disappointed that China is allowing oil to go into North Korea.”

The decision would totally hinder efforts to find a peaceful solution to the escalating tensions about North Korea’s nuclear program.

“Caught RED HANDED - very disappointed that China is allowing oil to go into North Korea. There will never be a friendly solution to the North Korea problem if this continues to happen!” President Trump tweeted.

Earlier in the day China responded to a report by a South Korean media outlet that claimed China had been providing North Korea oil illicitly by shipping vessels connecting at sea. China said that there had been no such sales breaking United Nations sanctions forbidding such activity.

As a counteractive measure to North Korea’s attempts to create missiles with nuclear capability able to strike the United States, the Trump administration has pushed a global initiative to increase worldwide condemnation and sanctions on Pyeongyang.

Critical to these attempts is the support of China, which is North Korea’s close neighbor and primary economic partner, says Washington. The Trump administration has also repeatedly made it clear that military actions are among the available options being considered in response to North Korea’s aggressive actions.

Following an intercontinental ballistic missile test by North Korea recently, the U.N. Security Council acted to increase the constraints on North Korea’s ability to access oil last week, specifically crude oil and refined petroleum products.

The latest sanctions by the U.N. attempt to prohibit almost 90 percent of refined petroleum products to North Korea with a yearly cap at 500,000 barrels.

The U.N. resolution, which was drafted by the United States, also limits the supply of crude oil to North Korea to 4 million barrels each year, with more penalties in the event of another nuclear test or ICBM launch by North Korea.