Chinese President Xi Jinping told Henry Kissinger that “old friends” like him will never be forgotten, striking an easy tone in their meeting in China’s capital on Thursday, amid efforts by Beijing and Washington to mend frayed ties.

“Once again, China and the US are at a crossroads of where to go from here, and once again, both sides need to make a choice,” Xi told the former US diplomat.

Kissinger played a key diplomatic role in normalising ties between Washington and Beijing in the 1970s when he served as secretary of state and national security advisor in the administrations of Presidents Richard Nixon and Gerald Ford.

Noting that Kissinger has just celebrated his 100th birthday and has visited China more than 100 times, Xi said his visit this time is of “special significance.”

“The Chinese people never forget their old friends, and Sino-U.S. relations will always be linked with the name of Henry Kissinger,” Xi told him at the Diaoyutai State Guesthouse, where foreign dignitaries are often received.

Kissinger, who is widely respected in China and has paid regular visits since leaving office, said he was grateful Beijing had arranged the meeting in the building where he had met with Chinese leaders during his first visit.

“The relationship between our two countries is a matter of world peace and the progress of human society,” China’s official news agency Xinhua cited Kissinger as saying.

“Under the current circumstances, it is imperative to maintain the principles established by the Shanghai Communique, appreciate the utmost importance China attaches to the one-China principle, and move the relationship in a positive direction,” Kissinger said in the meeting.

His visit to China comes at a time when the two superpowers are embarking on a course to stop their relations, already at historic lows, from sinking further.

The Chinese people never forget their old friends, and Sino-US relations will always be linked with the name of Henry Kissinger, says Chinese President Xi Jinping

“China is willing to discuss with the U.S. side the right way for the two countries to get along and promote the steady progress of China-U.S. relations,” Xi said.

China and the US can achieve mutual success and prosper together, he added, stressing the key is to follow the principles of “mutual respect, peaceful coexistence and win-win cooperation.”

Kissinger also met with China’s top diplomat Wang Yi and with defence minister Li Shangfu on his trip, which Washington said was a private visit.

Tensions between the world’s two largest economies have heightened over a range of issues, including the war in Ukraine, Taiwan and trade curbs.

Washington has tried to reestablish communication channels on these and other issues through recent high-profile diplomatic visits.

US presidential envoy John Kerry concluded lengthy talks with Beijing on fighting climate change on Wednesday and current Secretary of State Antony Blinken went to Beijing last month.