Japan, the United States and South Korea must still closely watch North Korea despite Pyongyang's recent gestures of detente, Prime Minister Yoshiro Mori and U.S. Defense Secretary William Cohen agreed Friday.

During their 30-minute meeting at the Prime Minister's Official Residence, Mori and Cohen shared the view that close teamwork by the three nations led to Pyongyang's recent diplomatic overtures and that the tripartite framework must be well maintained, a Foreign Ministry official told reporters.

Cohen arrived in Tokyo on Thursday night after a three-day visit to South Korea, which followed his trip to the Philippines, Singapore, Indonesia and Thailand.