DETROIT, July 24 (UPI) -- The campaigns of U.S. presidential hopefuls Barack Obama and John McCain have opened offices in Michigan, where the race is neck-and-neck, polls indicate.

The Detroit Free Press reported Thursday that Republican National Committee chairman Mike Duncan told a group of GOP volunteers in Farmington Hills, Mich., that the Wolverine State is up for grabs.

"Michigan is in play. There is absolutely no question that this is going to be ground zero," he was quoted by the newspaper as saying.

So far, McCain, the presumptive Republican nominee, has four GOP offices working on his behalf. A dozen others are expected to open in the coming weeks, Michigan Republican Party Chairman Saul Anuzis said.

On Wednesday evening, more than 1,000 people attended the official opening of Obama's Michigan headquarters in Detroit.

"We know what we have to do," state Sen. Tupac Hunter, D-Detroit, told the crowd. "We are the foot soldiers. We have the opportunity to shatter any voter turnout records Michigan has ever seen."

The Illinois Democrat's campaign is to open 21 offices in Michigan on Saturday and is expected to open another 20 in the next few weeks.