Beijing’s foreign ministry claimed Tuesday that a Canadian plane monitoring North Korea sanctions “harassed” China and undermined its sovereignty, disputing Ottawa’s contention that Chinese jets had endangered the aircraft.

The statement comes after the Canadian Armed Forces said on June 1 that Chinese air force planes violated air safety norms and flew dangerously close to a Canadian long-range patrol aircraft contributing to Operation NEON (Op NEON), a mission designed to support the implementation of U.N. sanctions on the DPRK.