The leaders of China and South Korea called for North Korea to resume negotiations on its nuclear disarmament after a meeting Thursday in which they discussed ways to draw their isolated and erratic neighbor back into dialogue with the outside world.

The summit in Beijing marked the beginning of a four-day visit by South Korea’s new president, Park Geun-hye. It also comes at a time when China, Pyongyang’s biggest ally and longtime benefactor, has signaled unusual displeasure with the North after it recently carried out a missile launch and nuclear test and issued a barrage of provocative rhetoric despite Beijing’s protests.

“We shared an understanding that North Korea’s possession of nuclear weapons cannot be tolerated under any circumstances,” Park said at a joint news conference with China’s President Xi Jinping.

Xi said that he and Park had agreed to work together on matters related to the North but put his emphasis on the need for Pyongyang to restart six-nation talks on nuclear disarmament.

In the days leading up to the meeting, Park made clear that North Korea was her overriding concern, telling South Korean media that she would try to boost cooperation with China “so as to make North Korea come forward for sincere talks.”

Underscoring her hope of strengthening and leveraging economic ties with China, Park was accompanied here by high-ranking executives from South Korea’s biggest companies, including Samsung, LG and Hyundai Motors. The unusually large 71-member business contingent highlights the enormous volume of trade between the two countries — worth $215 billion last year — and South Korea’s status as one of the few countries to post a trade surplus with China.

As for China, many analysts say it is using the meetings with Park to signal its displeasure with North Korea and increase pressure on the government there. Many note that Park is meeting with Xi before North Korea’s young new leader, Kim Jong Un, has had an opportunity to do so.

A visit by Kim to Beijing simply has not been possible given the recent chill in relations between China and the North, said Zhang Liangui, a North Korea expert at the Central Party School here, which is run by the ruling Communist Party.

“If the leaders of the two countries cannot agree on important issues, there cannot be a successful or a fruitful visit,” Zhang said.

Chinese officials are considered unlikely to abandon North Korea anytime soon, fearful of the instability, the swarms of refugees and the unified, U.S.-friendly Korean government that might ensue on its doorstep.

Still, after North Korea’s nuclear test this spring, China agreed to increased sanctions on its ally and cut off access for some North Korean banks.

“In the past, Chinese residents had some sympathy towards North Korea, more or less, but right now, Chinese are very disappointed and feel North Korea is almost laughable,” said Jin Canrong, an international relations professor at Renmin University in Beijing.

In the past, Jin added, China was reluctant to publicly discuss North Korean issues with the South or the United States, out of consideration for its ally’s feelings. “But now, China doesn’t care what North Korea thinks at all and discusses these agendas openly in public,” he said.

Many South Korean experts note that Park’s background positions her well to strengthen South Korean-Chinese ties. She taught herself to speak Mandarin earlier in life by watching TV programs and is reported to be fascinated by Chinese culture and philosophy. One Korean news service also reported that she would deliver portions of her speeches this week in Chinese — all details that China’s state-run media have played up in recent days.

Still to come on her trip are meetings with Chinese Prime Minister Li Keqiang and other leaders and a speech at Beijing’s Tsinghua University. Also on the itinerary is a trip to Xi’an — China’s ancient capital as well as the home of a $7 billion electronic chip manufacturing plant being built by Samsung.

Zhang Jie contributed to this report.