(Chicago, Ill.) Party officials say former President Clinton will deliver a speech on the third night of the Democratic National Convention before an address by the as-yet-to-be-named running mate for Barack Obama.

Exactly what role the former president would play at the gathering in Denver Aug. 25-28 has been the subject of speculation since his wife, New York Sen. Hillary Rodham Clinton, ended her bid for the Democratic presidential nomination in early June and endorsed Obama.

The officials spoke Thursday on condition of anonymity before the details were formally announced.

Obama clinched the nomination after a sometimes bitter primary contest with Sen. Clinton. She’s expected to speak on the convention’s second night.

Obama dismissed suggestions tension between his supporters and hers could upset the gathering.

Obama told reporters their staffs were working out mutually acceptable convention logistics. At the same time, Clinton was assuring her supporters during an online chat that she and Obama were “working together to make sure it’s a big success.”

Neither answered questions about whether Clinton’s name should be placed in nomination so that her backers could record their votes.

Amid reports that some Clinton backers hope to raise her profile at the convention or even continue to push her candidacy, Clinton and Obama were publicly trying to ease the strained relations that exist between some of their supporters.

Flying home to Chicago, Obama told reporters that he had talked separately this week to Clinton and her husband, and that they were enthusiastic about having a smooth convention.

“As is true in all conventions, we’re still working out the mechanics, the coordination,” Obama said. One such issue is whether there will be a convention roll call on Clinton’s nomination, he said.

“I’m letting our respective teams work out details,” he said.

During the online chat on her Web site, Clinton wrote that she and Obama will ensure Democrats are “fully unified.”

Clinton was expected to deliver a prime-time address to delegates on Aug. 26. With the delegate roll call planned for the next evening, Obama was set to accept the nomination with a speech on the convention’s fourth and final night.

“We will ensure that the voices of everyone who participated in this historic process are respected and our party is fully unified heading into the November election,” Clinton wrote. “While no decisions have been made yet, I will make sure that we keep you up to date and involved with all of the convention activity.”

Clinton insisted during the Web chat that she was sincerely behind Obama.