China's Wang Huning, a Communist Party Politburo Standing Committee member, has held talks in Pyongyang with Jo Yong-won, a top official of North Korea's ruling Workers' Party.
The Chinese delegation led by Wang arrived in Pyongyang on Wednesday at the invitation of North Korea, state media KCNA reported on Thursday.
At the meeting, Wang affirmed "the will of the Chinese party and the government" to implement the agreement reached between Chinese President Xi Jinping and North Korean leader Kim Jong-un during Xi's visit to Pyongyang, KCNA said.
He also referred to the 65th anniversary of friendship ties between the two countries, it added.
Jo told Wang that North Korea seeks to develop strategic communication and tactical cooperation with Beijing.
The two officials discussed ways to improve public welfare and to deepen mutual co-operation in business, culture and the ruling parties of the two countries, KCNA said, without elaborating.
Earlier in July, North Korean Premier Pak Thae-song met with Xi in Beijing during his visit for an event marking the 65th anniversary of the neighbours' friendship treaty.
Xi urged the two allies to maintain "strategic resolve" amid a turbulent global environment and to speed up implementation of agreements he reached with Kim.
The Treaty of Friendship, Co-operation and Mutual Assistance, signed on July 11 1961, remains China's only active mutual defence pact.