U.S. President George W. Bush and German Chancellor Angela Merkel on Tuesday agreed on the need to continue cooperating in dealing with the problem of Iran's nuclear development, Jiji Press reported. The two leaders met one on one on the sidelines of the three-day summit of the Group of Eight major nations, which started in this northern Japan resort town on Monday. Merkel said she is satisfied with progress in drafting a joint statement by the G-8 leaders on climate change and soaring oil and food prices, the main themes of the summit talks. She did not elaborate. Bush and Merkel also exchanged opinions about the Doha round of global trade liberalization talks, agreeing to aim for its early conclusion.