China’s top legislator met with a senior North Korean official for talks on cooperation during a visit to Pyongyang this week, North Korean state media said Friday, in one of the most high-level meetings between the allies in years.

Beijing’s third highest-ranking official Zhao Leji — a member of the powerful Standing Committee of the Chinese Communist Party’s Politburo — is on a goodwill visit to the nuclear-armed North as the two countries mark 75 years of diplomatic ties.

China is North Korea’s most important economic benefactor and diplomatic ally, obstructing US-led efforts at the UN Security Council alongside Russia to impose stricter sanctions on Kim Jong Un’s regime in response to its increased weapons tests.