In addition, Premier Wen Jiabao of China, President Lee Myung-bak of South Korea and Prime Minister Yoshihiko Noda of Japan agreed that their countries would work together to try to calm tensions on the Korean Peninsula.
North Korea is facing sanctions from United Nations Security Council after a failed rocket launch and threatened to conduct a third nuclear test.
“The pressing task is to try our best to prevent tensions on the Korean Peninsula from escalating,” Mr. Wen said. He urged all parties to “return to the right track of dialogue and negotiations.”
“The investment agreement is the first legal document on trilateral cooperation in the economic field, it is a milestone,” Wen said at a joint news conference at the Great Hall of the People.
Mr. Noda said Beijing, Tokyo and Seoul should work together to try to prevent further provocations by North Korea.
The agreement comes amid a slow global economic recovery.