The powerful sister of North Korean leader Kim Jong Un called a US push for the denuclearization of North Korea an “anachronistic dream,” saying Sunday the North will steadily expand its nuclear arsenal in the face of US-led threats.

The statement came a day before Chinese President Xi Jinping visits North Korea for talks with Kim Jong Un, in his first visit to the country in seven years.

“The US assertion to backbite the status of the DPRK as a nuclear weapons state has no legally binding force and no one will be bound by the US unilateral rhetoric,” said Kim's sister and senior official, Kim Yo Jong, using the abbreviation for North Korea’s official name.

She dismissed as “false information” a US announcement that President Donald Trump and Xi confirmed their shared goal to denuclearize North Korea in their summit in Beijing last month.

“Some officials in the United States have failed to wake from their escapist and anachronistic dream,” Kim Yo Jong said.

North Korea has been focusing on enlarging its nuclear arsenal since Kim Jong Un's high-stakes diplomacy with Trump collapsed in 2019. Experts say the North Korean leader wants international recognition as a nuclear state so that he could demand the lifting of international economic sanctions on North Korea.

During a visit to a new nuclear materials production plant last week, Kim Jong Un said North Korea would bolster the country’s nuclear forces “at an exponential rate.” On Sunday, North Korea's state media reported Kim Jong Un visited a weapons factory the previous day and called for increasing the country's missile production capacity 2.5 times under a five-year plan period.

In her statement, Kim Yo Jong accused the United States and South Korea of pushing for “ceaseless arms build-ups," saying her brother's push for “steadily beefing up the nuclear war deterrent for self-defense” is “an irreversible final conclusion to be carried out unconditionally.”

Analysts say Xi's visit to North Korea is largely meant to reassert China's influence over North Korea, whose foreign policy priority has shifted to Russia in recent years. They say Xi will likely refrain from directly raising the denuclearization issue and offer economic assistance programs during his meeting with Kim Jong Un.

North Korea has sent troops and conventional weapons to Russia to back its war efforts against Ukraine. South Korean and U.S. officials say North Korea has received economic and other assistance from Russia in return.