(CNN) -- Sen. John McCain's campaign again called Sen. Barack Obama a flip-flopper after the Democratic candidate held two news conferences to clarify his remarks on the Iraq war.
Obama on Thursday denied that he's shying away from his proposed 16-month phased withdrawal of all combat troops from Iraq, calling it "pure speculation" and adding that his "position has not changed."
However, he told reporters questioning his stance that he will "continue to refine" his policies as warranted.
His comments prompted the Republican National Committee to put out an e-mail saying the presumed Democratic nominee was backing away from his position on withdrawal.
Obama called a second news conference later Thursday to reiterate that he is not changing his position.
"Apparently I wasn't clear enough this morning on my position with respect to the war in Iraq. I have said throughout this campaign that this war was ill-conceived, that it was a strategic blunder and that it needs to come to an end," he said.
"I have also said that I would be deliberate and careful in how we got out, that we would bring our troops home at a pace of one to two brigades per month and that at that pace we would have our combat troops out in 16 months."
Obama on Friday appeared at a parade in Butte, Montana, alongside his wife, Michelle, and their two daughters.
"On this day when we celebrate this great nation of ours ... it's worth reminding ourselves that what makes this country great is not the size of our military or the size of our economy or the big buildings that we have. What makes us great is its people ... and all of you are part of what I celebrate when I think about America," he said.
McCain is taking the July Fourth weekend off after returning from a three-day trip to Colombia and Mexico.
Obama placed some of the blame for the confusion Thursday on the McCain camp.
"I think what's happened is that the McCain campaign primed the pump with the press to suggest that somehow we were changing our policy when we hadn't and that just hasn't been the case," Obama said.
"I've given no indication of a change in policy. I haven't suggested that we're moving in a different direction. I think John McCain's going to have a much harder time explaining how he is willing to perpetuate a presence in Iraq for 10, 20, 50 years."
The McCain campaign responded after the second news conference with a statement accusing Obama of reversing his position on Iraq.
"There is nothing wrong with changing your mind when the facts on the ground dictate it," the statement said. "Indeed, the facts have changed because of the success of the surge that John McCain advocated for years and Barack Obama opposed in a position that put politics ahead of country."
Obama made his first remarks Thursday on Iraq with reporters in Fargo, North Dakota, before holding a town hall-style meeting that many military veterans and their families attended.
"We're planning to visit Iraq," Obama said, referring to his recently announced trip for later this summer. "I'm going to do a thorough assessment when I'm there." Watch as Obama says he hasn't changed his stance on troop withdrawal »
Asked if he is open to options that wouldn't include the removal of all combat troops within 16 months, the senator from Illinois did not respond directly but said he will continue to "gather information."
On April 10, Obama told an Indiana crowd it may take "16 months to two years" to remove combat troops. In recent speeches, he's left out the phrase "16 months" entirely.
Democratic strategist and CNN contributor Paul Begala, who worked in the Clinton White House, had some advice for Obama: "If I were to give him a little coaching advice, it would be don't answer hypothetical questions."
Earlier this week, McCain said, "I don't switch my position depending on what audience or what time it is in the electoral calendar. ... I believe that [voters] will more and more see where Sen. Obama has switched his positions on fundamental issues. The one thing they want is trust and confidence in their leadership, and I think I will win in that area."
While campaigning in North Dakota, Obama said McCain "is a person who opposed [President] Bush's tax cuts before he was for them, who opposed drilling in the continental shelf before he was for [it]. [McCain] has reversed himself on a range of very substantive issues during the course of this campaign, and so I'd be happy to have a debate about consistency with John McCain."
CNN's Paul Steinhauser, Chris Welch and Jessica Yellin contributed to this report