China has expressed concern Monday over North Korea’s repeated threats to test-launch an intercontinental ballistic missile. On Sunday, Pyongyang had blamed the U.S. for the isolated country’s nuclear and missile tests and warned it would test-launch the ICBM at any time from any place chosen by leader Kim Jong Un.

“We are seriously concerned over this… We call on all sides to refrain from actions that could escalate the situation. We will closely monitor the situation and try to contribute to upholding peace and stability on the peninsula,” Chinese foreign ministry spokesman Lu Kang said.

“The United Nations Security Council has clear rules for North Korea regarding its use of ICBM technology to test missiles. In this complex and sensitive situation, China asks all relevant parties to not engage in acts that will raise tensions,” Lu added.

North Korea’s foreign ministry had said that it developed the ICBM to strengthen its self-defense capabilities to counter “the ever more undisguised nuclear war threat from the U.S.” The ministry also said that the North developed hydrogen bomb and “had access to standardized nuclear warheads by bolstering up its nuclear weapons on a high level at an unimaginably high speed on the strength of self-development” despite the sanctions from the United Nations and world powers.

“The ICBM will be launched anytime and anywhere determined by the supreme headquarters of the DPRK [Democratic People’s Republic of Korea],” the North Korean foreign ministry said.

Also on Sunday, U.S. Defense Secretary Ash Carter said Washington would shoot down the North’s ballistic missile and called the country’s nuclear weapons capabilities and ballistic missile defense programs a “serious threat” to the U.S.

“We only would shoot them down ... if it was threatening, that is if it were coming toward our territory or the territory of our friends and allies,” Carter said.