Chinese Premier Wen Jiabao warned Sunday that Asia faced an \"unstable and uncertain\" situation as he sat down with leaders of Japan and South Korea for talks 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 coordination.\" Japan Prime Minister Yoshihiko Noda said prior to his departure for the summit, also attended by South Korean President Lee Myung-Bak, 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 United States 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 environment issues. Later 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 cooperation,\" Noda said Sunday. 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.