Chinese Premier Li Keqiang has begun talks with South Korean President Park Geun-hye, likely to focus on North Korea. The two leaders will also attend a regional summit with Japan on Sunday, aimed at improving relations.
North Korea was expected to be high on the agenda during Li and Park's bilateral talks in Seoul on Saturday, amid fears Pyongyang could be preparing to conduct another nuclear test.
The pair were meeting ahead of a three-way regional summit, which is due to begin on Sunday, with Japanese Prime Minister Shinzo Abe.
Tensions on the Korean peninsula have eased in recent months after North Korea abandoned plans to conduct a long-range rocket launch during the 70th anniversary celebrations of the ruling Workers' Party.
While China and South Korea already have strong trade ties, Seoul wants Beijing to exercise its considerable leverage over Pyongyang to curb the North's nuclear ambitions. Beijing is one of North Korean leader Kim Jong-un's few allies.
Following a recent flare-up between Washington and Beijing over the US Navy's operations close to a group of disputed islands in the South China Sea, analysts said Li may also seek assurance from Park that Seoul, a key US ally, will retain its neutral stance.
China claims nearly all of the South China Sea, but Washington says the waters are international territory and earlier this week, sailed a warship close to the islands.
Relations between Northeast Asia's three largest economies have remained tense over the past three years. After the last trilateral summit in 2012, regional talks were shelved as Japan's ties with its two neighbors deteriorated over Tokyo's wartime aggression.
A Sino-Japanese dispute over a separate group of islands in the East China Sea has also been a source of ill-feeling.
Warmer ties ahead
Diplomats agreed to renew contact last November, when Chinese President Xi Jinping briefly met and shook hands with Abe.
Park will separately meet Abe on Monday in the first formal bilateral summit in more than three years.
Seoul's ties with Tokyo have been persistently icy, stemming from Japan's brutal colonial rule of the Korean Peninsula in the early 20th century. China has similar gripes with Japan.
While the talks are unlikely to bring about any major policy change, analysts believe they are the first step toward overcoming some bitter differences.
mm/ng (AP, AFP, dpa)