DENVER -- Confirming rumors that surfaced last week, the Democratic National Committee announced Monday that Sen. Barack Obama will make his party's nomination acceptance speech at Invesco Field at Mile High instead of at the Pepsi Center, where most of the party's convention will be held.

The reason for the move is to open the event up to the public and to allow tens of thousands of more people to actively participate in the process, DNC officials said.

The Pepsi Center can hold 21,000 people for special events but Invesco Field at Mile High, the outdoor stadium where the Denver Broncos play, can seat more than 76,000 -- not including the thousands of seats that could be placed out on the field.

"When we said we wanted to 'bring down the walls,' open up this convention like never before and truly speak to the American people, we meant it," said Leah D. Daughtry, chief executive officer of the Democratic National Committee Convention. "On Aug. 28, we will offer grassroots Democrats, who have turned out in record numbers this year, the opportunity to witness history shoulder to shoulder with thousands of Americans standing up for the change our country desperately needs."

A special block of "community" credentials will be reserved for Colorado residents for Thursday night's program at Invesco Field. Details about how to sign up and receive a "community credential" for the last night of the convention will be released in the coming weeks.

The Pepsi Center will still be host to the Democratic National Convention the first three nights -- from Aug. 25 through Aug. 27 -- but the last and final night will be moved to Invesco Field.

"Senator Obama and the DNCC have truly brought the community into the convention," said Gov. Bill Ritter. "This decision will enable thousands of residents from Colorado, the Rocky Mountain West and across the nation to witness history first hand. What a way to fire up our grassroots activists as we head into the fall campaign."

Aug. 28 also happens to be the 45th anniversary of Martin Luther King Jr.'s "I Have a Dream" speech, given to tens of thousands at The Mall in Washington, D.C.

Although it is a surprise to move Obama's acceptance speech to the football stadium -- versus the more traditional, indoor arena setting -- it is not unprecedented. In 1960, the Democratic National Convention was held at the Los Angeles Memorial Sports Arena but nominee John F. Kennedy delivered his acceptance speech next door at the Memorial Coliseum.

"Senator Obama's candidacy has generated an enormous amount of excitement and interest, not only in the Democratic Party but also in the 2008 convention. By bringing the last night of the convention out to the people, we will be able to showcase Barack Obama's positive, people-centered vision for our country in a big way," said former Vermont Gov. Howard Dean, chairman of the Democratic National Committee.

The Republicans immediately criticized the move.

"I really can't believe that Senator Obama wants to heap yet more expense on the city of Denver by moving his nomination speech from the Pepsi Center to Invesco Field," said Dick Wadhams, chairman of Colorado Republican Party. "The Democrats are already $11 million short of their goal and now Senator Obama is having the discourtesy of piling more debt on the Democratic Party here in Colorado for the convention. I think it's unfortunate. My heart goes out to the Democratic party in Colorado for this unbelievable show of discourtesy by Sen. Obama."

Obama ally and convention co-chair Gov. Kathleen Sebelius, of Kansas, defended the plan.

"Barack Obama's campaign for change has inspired millions of Americans and brought people into the political process who might never have been involved," she said. "This change in the convention program will allow thousands of first-time participants a chance to take part. I can't think of a better convention finale for our nominee who has made reaching out to voters a hallmark of his campaign."