Chinese President Xi Jinping and his South Korean counterpart Moon Jae In have sought to patch up ties hit by Seoul's deployment of an anti-missile system that Beijing says hurts its security interests.

Mr Xi told Mr Moon his visit would improve bilateral relations that have suffered a setback, while the South Korean leader called for a "new start" to ties at their summit in Beijing yesterday. The North Korean nuclear issue was also top on the two leaders' minds, with both sides stressing the need to resolve the issue via peaceful means and for the denuclearisation of the Korean peninsula. They also said they would not tolerate war on the peninsula.

Mr Moon's first state visit to China after taking office in May comes at a time when bilateral ties have cooled markedly over South Korea's deployment of the American Terminal High Altitude Area Defence (Thaad) anti-missile system against the North's nuclear threat. China objected to this, saying the system compromised its security interests.

In retaliation, Beijing banned group tours to South Korea and cracked down on South Korean firms operating in China, among other measures. South Korea's central bank said China's moves shaved 0.3 percentage point off the country's growth this year, reported Bloomberg News.

The two sides in a joint statement in late October agreed to improve ties and Mr Moon's visit is meant to do just that, including getting economic exchanges back on track.

Acknowledging "temporary difficulties", Mr Moon told Mr Xi: "I would like to build a solid foundation for opening up a new era in the relationship between our two countries, based on trust and friendship between us two leaders."

Mr Xi, for his part, said: "For reasons known to all, China-South Korea relations have experienced some setbacks." He added: "I hope and believe that your visit will be an important opportunity to improve relations as we seek to find ways to carve a better path based on mutual respect and trust."

The two leaders also agreed to set up a direct hotline of communication. They later oversaw the signing of several memorandums of understanding, including on starting negotiations to upgrade their bilateral free trade agreement.

Yesterday morning, Mr Moon visited a trade fair. About a dozen South Korean journalists were following him out of the venue of the fair, organised by the Korea Trade-Investment Promotion Agency, when they were stopped by Chinese security guards. One photojournalist was surrounded by 15 guards and knocked to the ground. When another intervened, he was beaten up, said media reports.

"Emergency medical treatment was provided at the scene, and (the South Korean) government has expressed regret to the Chinese government, and strongly requested a clear investigation and follow-up measures," the South Korean Ministry of Foreign Affairs was quoted as saying by South Korean media.

This afternoon, Mr Moon will meet Premier Li Keqiang and parliamentary chief Zhang Dejiang before flying off to the western city of Chongqing. In the morning, he will speak to Peking University students on the topic of cooperation between the two countries' young people to create a bright future together.

But in a sign that Thaad is not yet behind the two neighbours as they look to boost ties, Mr Xi reiterated China's stand on the issue, according to CCTV news. Seoul has said it would not deploy additional Thaad batteries, but it appears this is not enough for the Chinese.

Mr Xi told Mr Moon he hoped South Korea would "continue to deal with the issue appropriately".

• Additional reporting by Chang May Choon in Seoul