WASHINGTON - President Barack Obama shrugged off the suggestion by a top Mitt Romney adviser that former Secretary of State Colin Powell's endorsement of Obama was due to race rather than support for his positions.

"Any suggestion that General Powell would make such a profound statement in such an important election based on anything other than what he thought was best for America, I think, doesn't make much sense," Obama told radio host Michael Smerconish.

US President Barack Obama meets with former Secretary of State Colin Powell (L) in the Oval Office at the White House in Washington in this Dec 1, 2010 file photograph. [Photo/Agencies]

Obama and Republican challenger Romney are locked in a tight battle before the Nov 6 election. Both campaigns are in high gear as Election Day draws near and any controversy or gaffe gets attention.

Smerconish asked Obama in an interview released on Friday whether he was offended by Sununu's remarks.

Sununu, a former New Hampshire governor and chief of staff to former President George H.W. Bush, was asked to comment on Powell's endorsement of the Democratic president, and whether Powell, a Republican, should leave the party.

Sununu, who co-chairs the Romney campaign, said Powell, who was secretary of state under President George W. Bush, might have had an another reason for giving his support to Obama.

"When you take a look at Colin Powell, you have to look at whether that's an endorsement based on issues or he's got a slightly different reason for endorsing President Obama," he said during an interview with CNN's Piers Morgan.

Pressed what that reason was, Sununu suggested it might be because, like Obama, Powell is black.

"When you have somebody of your own race that you're proud of being president of the United States, I applaud Colin for standing with him," Sununu said.

When the comment stirred controversy, Sununu backed away, saying Powell's backing of Obama was undoubtedly based on the president's policies.

"Colin Powell is a friend and I respect the endorsement decision he made, I do not doubt that it was based on anything but his support of the President's policies," Sununu said in a statement. "Piers Morgan's question was whether Colin Powell should leave the party, and I don't think he should."

Obama said Powell's statement of support spoke for itself.

"He spoke about the fact that my foreign policy during a very difficult time had been steady and strong," the president said. "He talked about with respect to our economy, that we had helped to rescue America from a potential great depression and that we were moving in the right direction."

In endorsing Obama on Thursday, Powell cited the president's efforts to wind down the war in Afghanistan and tackle terrorism as well as an improving US economy.

"I voted for him in 2008 and I plan to stick with him in 2012," Powell told "CBS This Morning."