The top diplomats of the United States and China held tough talks in Beijing on Friday, as the rival superpowers sought to clarify their growing differences on an array of bilateral and global issues that could further strain the already tense relationship.

While claiming that ties are “beginning to stabilize,” U.S. Secretary of State Antony Blinken and his Chinese counterpart, Wang Yi, did not mince words when addressing a raft of contentious topics, including trade, Ukraine and Taiwan.

At the start of a meeting at Beijing’s Diaoyutai State Guesthouse, Wang warned Washington not to cross China’s red lines on sovereignty, security and development, adding that “negative factors” have been mounting between the world’s two largest economies as the relationship “faces all kinds of disruptions.”