TOKYO, Sept. 3 (Xinhua) -- The Democratic Party of Japan (DPJ) President Yukio Hatoyama met Thursday with new U.S. Ambassador to Japan John Roos on bilateral relations amid concerns over a possible change in the Japan-U.S. alliance after the DPJ assumes power.

    The talks were held "in a quite comfortable atmosphere," Hatoyama told reporters.

    And both sides agreed to further develop bilateral ties, he said.

    Referring to Hatoyama as the "future prime minister, Roos said that they had "a wonderful meeting, a very warm meeting."

    "We spent a lot of time talking about how to enhance and further deepen the relationship across a broad range of issues, not only strategic issues, but scientific issues, cultural matters," he said after the talks.

    Also in the day, Hatoyama held talks with Russian Ambassador Mikhail Bely, who said that the DPJ's big win reflects the Japanese people's trust in the party and expectations for the country's development.

    The Russian envoy conveyed congratulations to Hatoyama from Russian President Dmitry Medvedev and Prime Minister Vladimir Putin.