After four days of high stakes a trip to ChinaUS Treasury Secretary Janet Yellen said she had a “constructive visit” and “a very crucial series of meetings” with Chinese officials on the state of the global economy, export controls and national security.

Yellen’s trip is part of ongoing efforts to stabilize relations between the US and China after months of escalating tensions. Her visit came just a few weeks after the foreign minister Antony Blinken’s visit last month.

These efforts could eventually pave the way for a meeting with the US president Joe Biden and the Chinese president You are Jinping on the sidelines of the G-20 leaders’ summit in New Delhi in September and the APEC leaders’ summit in San Francisco in November. The two leaders last met last year in Bali.

“We have a new economic team in Beijing that is important for establishing personal relationships and opening ongoing channels of communication where concerns can be aired and discussed,” Yellen told CBS’ “Face the Nation.” ” Sunday. “And I think my trip was successful in establishing those relationships and creating an opportunity for a deeper set of more frequent contacts at our staff level.

Yellen’s task in Beijing was complex. She said she raised a range of concerns, including national security and intimidation faced by some US companies, but also sought Chinese cooperation on issues ranging from climate change to the debt crisis.

Yellen said her purpose was to ensure that the two nations did not engage in “unintended escalating actions that will be detrimental to our overall economic relationship with each other.”

For example, just days before Yellen’s visit, Beijing imposed export restrictions metal shavings and compounds. Chinese Ministry of Commerce he claimed it did US and Europe in advance. In October, the US launched sweeping rules focused on cut off export key chips and semiconductor tools to China.

Yellen said she expressed concern about export controls and compared it to the US decision. She explained that the US actions “are narrowly focused on addressing national security concerns,” although it is not clear that China’s export controls were put in place for the same reason.

“We’ve had very little contact, both with senior officials and just with the American people and the Chinese people, who have been very little in touch over the last few years, partly because of Covid,” Yellen said. “And that’s where a misunderstanding can occur.”

Yellen said China is also taking steps to address concerns about a slowing economy and that there are opportunities for American businesses to profit.

But she still said national security remains a priority for the US

“China has a huge market. It’s a significant share of the global economy, and we want to make sure that American businesses and workers can benefit from that and contribute to China’s success and ours,” Yellen said. “But there are areas where national security really requires us to withhold the most advanced technologies with military applications to protect our own national security. And we have acted and will continue to act on that.”

— CNBC’s Clement Tan contributed to this report.