A high-level defector from North Korea warned in a new interview that Kim Jong Un would use nuclear weapons against the U.S. or its allies to stay in power if necessary.

Thae Yong Ho, who was deputy ambassador to the United Kingdom when he defected in 2016, told NBC News that the North Korean dictator was “desperate in maintaining his rule.” Thae’s defection was the most significant in years, making him uniquely informed about Kim’s rule, though he wasn’t a part of the nuclear weapons program.

“Once [Kim] sees that there is any kind of sign of a tank or an imminent threat from America, then he would use his nuclear weapons with ICBM,” Thae said, referring to intercontinental ballistic missiles.

Kim has stepped up nuclear and missile testing recently. President Donald Trump said Sunday that he will discuss North Korea’s nuclear program with Chinese President Xi Jinping during their meeting this week, and that he believes China should take a more active role in curbing North Korea’s nuclear development.

[NBC]

Get The Brief. Sign up to receive the top stories you need to know right now. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Julia Zorthian at julia.zorthian@time.com.