Wen Jiabao, China's premier, has warned that Asia faced an "unstable and uncertain" situation as he sat down with leaders of Japan and South Korea for discussions likely to focus on dealing with North Korea.
A trilateral free trade pact was also expected to be near the top of the agenda during the day of talks in Beijing among the leaders of Northeast Asia's three dominant powers.
"The Northeast Asia and East Asia regions are faced with a lot of unstable and uncertain elements that are difficult to predict," Wen said in his opening remarks.
"At this important moment, it is significant for maintaining regional peace and development that the leaders of China, Japan and South Korea exchange views on issues of common interest and strengthen their co-ordination."
Yoshihiko Noda, Japan's prime minister, said prior to his departure for the summit, also attended by Lee Myung-Bak, South Korea's president, that the three nations would step up efforts to prevent a possible North Korean nuclear test.
Fears of a test have grown after a failed rocket launch by Pyongyang last month that the US and its allies said was a disguised ballistic-missile test banned under UN resolutions.
In addition to North Korea, Wen and the other two leaders will discuss a wide range of subjects, including economic and environmental issues.
Economic and trade ministers of the three nations meeting in Beijing on Saturday decided to recommend that negotiations on a free-trade pact should start before the end of 2012, the state-run China Daily newspaper reported.
Al Jazeera's Harry Fawcett, reporting from Seoul, said: "As a whole, these three economies make up a fifth of the world economy, so the idea of a full, free-trade area encompassing these three countries would be seen as a very significant development.
"It would be one which would rival in size, and probably in power, the North American Free Trade Area, and the European Union."
Later on Sunday, the three nations will sign an investment agreement which was concluded in March after 13 rounds of negotiations taking place since 2007.
"This marks important progress for our co-operation," Noda said on Sunday.
Source: Al Jazeera and Agencies