UNITED NATIONS (Reuters) - China’s new U.N. ambassador warned on Friday that if the United States wanted to fight China on trade “then we will fight,” and signaled that trade tensions could hurt cooperation between the countries on dealing with North Korea.

FILE PHOTO: The head of the Chinese delegation Assistant Minister of Foreign Affairs Zhang Jun delivers his opening remarks during a Treaty on the Non-Proliferation of Nuclear Weapons (NPT) conference with the UN Security Council's five permanent members (P5) China, France, Russia, Britain, and U.S., in Beijing, China, January 30, 2019. REUTERS/Thomas Peter/Pool

U.S. President Donald Trump vowed on Thursday to slap a 10% tariff on $300 billion of Chinese imports from next month, sharply escalating a trade dispute between the world’s biggest economies.

In unusually blunt remarks for a United Nations’ diplomat from China, Zhang Jun described Trump’s move as “an irrational, irresponsible act” and urged Washington to “come back to the right track.” He also said Beijing was prepared to take countermeasures.

“China’s position is very clear that if U.S. wishes to talk, then we will talk, if they want to fight, then we will fight,” Zhang said. “We definitely will take whatever necessary countermeasures to protect our fundamental right, and we also urge the United States to come back to the right track in finding the right solution through the right way.”

Zhang served as an assistant minister for foreign affairs in Beijing before beginning his role as U.N. ambassador this week. He spoke to a small group of reporters at U.N. headquarters.

When asked if China’s trade relations with the United States could harm cooperation between the countries to deal with North Korea, Zhang said it was difficult to predict.

But he added: “It will be hard to imagine that on the one hand you are seeking the cooperation from your partner, and on the other hand you are hurting the interests of your partner.”

As North Korea’s ally and neighbor, China has played a key role in agreeing to and enforcing U.N. Security Council sanctions on Pyongyang over its nuclear and ballistic missile programs.

Since Trump and North Korean leader Kim Jong Un met for the first time a year ago, China has signaled Pyongyang should be encouraged and that “at an appropriate time” sanctions should be eased. He added that China had not decided when that should be.

“You cannot simply ask DPRK to do as much as possible while you maintain the sanctions against DPRK, that definitely is not helpful,” he said, using North Korea’s official name - the Democratic People’s Republic of Korea.

Zhang also said that while he was very willing to cooperate with other U.N. member states, China would never allow interference in the country’s “internal affairs, especially on issues related to Xinjiang, Tibet, and to Hong Kong.”

China has been widely condemned for setting up detention complexes in remote Xinjiang, where the U.N. says at least 1 million ethnic Uighurs and other Muslims have been detained. Beijing describes them as “education training centers” helping to stamp out extremism and give people new skills.

In Hong Kong, protests against a proposed bill that would allow people to be extradited to stand trial in mainland China have grown increasingly violent, with police accused of excessive use of force and failing to protect protesters from suspected gang attacks.

“The demonstration has gone far beyond the nature of a peaceful demonstration, it’s really turning out to be chaotic and violent and we should no longer allow them to continue this reprehensible behavior,” Zhang said.