North Korea’s foreign ministry questioned the impartiality of U.N. Secretary-General António Guterres on Sunday, accusing him of pouring “gasoline over flames” by endorsing Pyongyang’s denuclearization.

The statement came after Guterres met with South Korean President Yoon Suk-yeol on Friday and expressed his “full support for the complete, verifiable and irreversible denuclearization (CVID) of the Korean Peninsula, and especially that of the DPRK,” according to the presidential office.