Special Report: U.S. presidential election 2008

U.S. Democratic presidential candidate Senator Barack Obama (R) speaks as U.S. Democratic vice presidential candidate Joe Biden looks on beside at the 2008 Democratic National Convention in Denver, Colorado of the United States Aug. 27, 2008. Barack Obama was announced the winner of the Democratic presidential nominee after the routine roll call and Joe Biden accepted the nomination as the Democratic vice presidential candidate on Wednesday at the national convention in Denver. (Xinhua/Zhang Yan) Photo Gallery>>>

    DENVER, the United States, Aug. 27 (Xinhua) -- Barack Obama, who surprised the Democratic National Convention on Wednesday night in Denver, Colorado, after Joe Biden accepted the nomination as his vice presidential candidate.

    Obama, who was expected to show up at the convention to deliver his acceptance speech, came out from the sideline of the stage as Biden and his wife were leaving, and stirring high heat among thousands of Democrats at present.

U.S. Democratic vice presidential candidate Senator Joe Biden (D-DE) addresses the 2008 Democratic National Convention in Denver, Colorado, Aug. 27, 2008.  (Xinhua/Reuters Photo) Photo Gallery>>>

    He applauded for Biden's nomination, saying he is proud to have him as the running mate.

    Obama also expressed gratitude to his former rival, Hillary Rodham Clinton, for calling voters to support him and reminding people to "put country first."

    After voting by voice earlier the night, Nancy Pelosi, House Speaker, announced said that since there is no objection to the nomination of Biden and no second candidate, the Delaware Senator won the nomination.

    "Yes, yes, I accept your nomination to run and serve alongside our next President of the United States of America, Barack Obama," Biden said in his acceptance speech.

    He highlighted his experience in foreign and national security policies, saying he found after visits to Georgia, Iraq, Pakistan and Afghanistan "this administration's policy has been an abject failure," so "America cannot afford four more years of this."

    Biden stepped aside and offered applause to Obama, who is expected to make a change, transform the country's economy and bring down the cost of health care, among others.

    The 65-year-old Senator who has been co-working with Republican presidential candidate John McCain for decades, did not wait to launch attacks at his "old friend."

    By comparing McCain's policies in the Iraq and Afghanistan wars as well as the Iran nuclear issue with Obama's, he noted that the Democratic presidential hopeful's judgment is trustable.

    Obama has been criticized by McCain's campaign for lacking experience in politics, especially in foreign and defense affairs.

    Biden, the current chairman of the Senate Foreign Relations Committee is considered as a "valuable asset" to compensate for Obama's shortcoming.