Special Report: U.S. presidential election 2008

    WASHINGTON, April 25 (Xinhua) -- Senator Hillary Clinton of New York and Senator Barrack Obama of Illinois are locked in a tight race ahead of the May 6 presidential primary in Indiana, according to a new poll released Friday.

    The CNN poll shows the two Democrats are tied at 45 percent each, with 10 percent of respondents unsure.

    The poll consists of three surveys: Research 2000 (April 23-24),ARG (April 23-24), and The Indianapolis Star (April 20-23).

    All polls include interviews conducted after the April 22 Pennsylvania primary, which Clinton won Tuesday by about 55 percent to 45 percent.

    The polls also show both candidates are strong with constituencies that backed them in other states: Clinton easily wins among senior citizens and women, while Obama has the advantage with young voters.

    With the campaign settled into a seemingly endless slugfest, roughly two-thirds of people in a separate survey done by the Pew Research Center said the race has gone on "too long."

    Half of those polled said the campaign has become "too negative."

    With nine primaries left before June 3, May 6 primaries in Indiana and North Carolina are the next front in the Democratic nomination fight where 187 delegates are at stake.

    Clinton's advisers appear to be focusing most efforts on Indiana, where demographics have proven friendlier to the former first lady.

    Obama has a significant lead in the polls in North Carolina and is heavily favored to win there.

    African-Americans are expected to make up around 40 percent of North Carolina primary electorate, giving him a healthy starting point.