China’s foreign ministry said on Thursday that Yang Jiechi, Wang’s predecessor and Xi’s top aide on foreign affairs, would visit Japan on Friday. His trip is expected to pave the way for Xi’s high stakes visit in the spring, observers said.

But Benoit Hardy-Chartrand, an international affairs expert at Temple University in Tokyo, said that if the outbreak did not subside in the next few weeks, Japanese Prime Minister Shinzo Abe’s government would come under intense pressure to delay the visit.

“Despite reassuring official pronouncements, no one would be surprised if the visit was postponed to a later date,” he said. “With an already declining approval rate, the Abe administration would be hard-pressed to go ahead with the summit.”

During her phone call with Wang, South Korean Foreign Minister Kang Kyung-wha urged China to refrain from carrying out what she described as “excessive” restrictions and forcible quarantine measures against visitors from her country, the Yonhap news agency reported.

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In the cities of Qingdao and Weihai in east China’s Shandong province – both of which are home to large South Korean and Japanese communities – local authorities have begun to quarantine arrivals from the two countries, while similar measures targeting South Koreans in particular have been introduced in Shenyang and Nanjing.

This is the first time China, where the coronavirus originated and which earlier criticised other nations for overreacting to the outbreak, has introduced country-specific measures in the name of disease control.

The move sparked fierce criticism in South Korea, with more than 750,000 people signing an online petition calling for a ban on Chinese visitors.

The foreign ministry in Seoul said that about 40 nations and regions had imposed some sort of restrictions on South Korean visitors.

Both South Korea and Japan – which were among the first to offer support and aid to China when the epidemic took hold – have imposed only partial restrictions on Chinese travellers, mostly those from Hubei, the province at the centre of the contagion.

Wang again thanked South Korea for its support and defended China’s control measures, saying they were necessary to reduce the cross-border movement of people and restrict the spread of the disease, China’s foreign ministry said.

Yonhap said both Wang and Kang also agreed that Xi’s proposed trip to South Korea in the first half of the year would proceed as planned.

Chinese experts said the coronavirus had deepened distrust and antagonism towards China in both countries, with many South Koreans and Japanese blaming China for the spread of the disease.

Li Wen, an expert from the China Institute of International Studies, said the coronavirus crisis had seen the rise of the “China threat” in South Korea, with its government under enormous pressure to get tough on its giant neighbour.

According to Yonhap, Kang urged South Korean diplomats in China earlier this month to help minimise any negative impact the epidemic might have had on relations between the two countries.

Hardy-Chartrand said relations between China and South Korea remained tense because of Seoul’s deployment of the American-made THAAD missile defence system, which in turn led to Beijing introducing unofficial sanctions that caused resentment among South Koreans.

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But the latest spat over the control measures was unlikely to be a major obstacle to regional relations, he said.

“Overall, cooperation on so-called soft issues like public health, as we are witnessing at the moment, can provide an opportunity for further improvement in the broader relationship, at least in the short term,” he said.

China-Japan relations might also benefit from closer cooperation on disease control given uncertainty in the region over the US-China trade war, the North Korean denuclearisation impasse, the United States’ commitment to its allies, and the coronavirus outbreak, he said.

“I am less sanguine about the mid- to long-term prospects for Sino-Japanese relations, given that the sources of the tensions that we saw from 2010 to 2017, namely the East China Sea territorial dispute and other historical issues, remain wholly unresolved,” he said.

According to a Pew study in December, 85 per cent of Japanese have an unfavourable view of China, the highest among 34 countries surveyed, while 63 per cent of South Koreans see China negatively.