WASHINGTON, April 28 (Xinhua) -- U.S. Democratic Presidential candidate Barack Obama's lead in the national poll has shrunk to zero after his rival, Hillary Rodham Clinton, won the Pennsylvania primary on April 22, said a poll released on Monday.

    According to the Gallup poll conducted on April 24 to 26, Illinois Senator Obama and New York Senator Clinton are now dead even at 47 percent among 1,240 Democratic and Democratic-leaning voters.

U.S. Democratic presidential candidate Senator Hillary Clinton speaks to supporters during a campaign stop in South Bend, Indiana April 26, 2008.

It was the second survey that has been made after Clinton's win on Tuesday in Pennsylvania with nearly 10 percentage points lead over Obama.

    These results "suggest that Democratic voters are -- for the moment at least -- divided right down the middle as to which candidate they most want to represent their party in November's general election," the poll says.

    The polling body also found in the latest survey conducted among national registered voters from April 22 to 26 that Clinton maintains her advantage over Republican presumptive presidential candidate, Arizona Senator John McCain, in the general election preferences at 47 percent to 44 percent.

    Obama and McCain are tied at 45 percent each, it added.

U.S. Senator and democratic presidential hopeful Barack Obama waves to supporters as he is introduced during a campaign stop in Kokomo, Indiana April 25, 2008.