DENVER - Some Wyoming and Colorado Democratic National Convention delegates were perplexed Wednesday when they were forced to cast their ballots in the morning, unable to release them to Barack Obama.

Some Obama supporters complained that Colorado Democratic leaders may be prolonging a party rift because Clinton backers weren't allowed to switch their votes to Obama, the Democratic Party nominee, in a show of unity before he won the nomination.

Both states' delegates voted before they met with Clinton.

Colorado Democratic Party chair Pat Waak delivered votes on the third day of the convention, giving 55 votes to Obama and 15 to Clinton.

Obama won the nomination when Clinton delivered New York's votes and moved that he be nominated by acclamation.

Waak said the morning vote was the only one the delegation would take, meaning there was no chance for Clinton supporters to change their vote to Obama.

"This is the only vote," she said, explaining it would be disruptive to try to take a second poll on the convention floor among the 70 delegates.

That upset Shawn Coleman, an Obama delegate from Boulder, Colo., who wanted a second round to allow the delegates to show full support for Obama.

"I understand that the Clinton delegates want to serve their constituents. That is what I'm doing, but I don't want this to be a hollow victory for Obama," he said.

Wyoming state Sen. Mike Massie, D-Laramie, said his delegation gave 12 votes to Obama and six to Clinton after state party officials rejected a request from Clinton delegates to delay the vote until after a meeting later in the day with Clinton. The vote was suspended before Wyoming could deliver its votes at the convention, but the party secretary declared that the votes that had been cast would stand.

"The reply was that they needed to vote at breakfast. The Clinton delegates thought to be fair to the process, that meant they had to vote for Clinton because they had not been released. They made it clear that all six are still committed to vote for Obama," Massie said.

Massie said the delegation is still puzzled by orders to vote before Clinton could meet with her delegates.

"That question is on the minds of a lot of people," Massie said.

Colorado Rep. John Salazar said he was surprised by the decision and called it unusual, but he said he would support it.

"I think it's part of the healing process. I think after tonight's vote, we're going to be a united party and support Obama. A divided party will never win," he said.

State Rep. Terrance Carroll of Denver said he never expected a second vote.

"We know there are delegates loyal to Clinton. It's OK. It's part of the process," he said.

It wasn't immediately clear how many other states allowed only one ballot within their delegations.

Clinton backers in Colorado had their own concerns, worried that there would be no state-by-state roll call to record the New York senator's strong showing.

"If we don't have an official roll call vote state-by-state, it is going to reopen a wound," said Sonja Jaquez Lewis, a Clinton delegate from Boulder County.

Lewis said if Clinton had been denied a roll call, she and others were prepared to walk out. But she said she would do whatever Clinton asked her delegates to do.