Democrat Barack Obama holds a 5-point lead over Republican John McCain, with little immediate indication their final public debate did much to sway the US presidential race, a Reuters/C-SPAN/ZOGBY poll showed on Friday.

Obama's edge over McCain held steady at 49 percent to 44 percent among likely US voters in the four-day tracking poll, unchanged from results before the two men met on Wednesday for their third and last debate before the Nov. 4 election.

The poll of 1,210 likely voters had a margin of error of 2.9 percentage points.

Pollster John Zogby said Friday's results -- in which the most recent day's results are added and the oldest day's results are dropped in an effort to measure changing momentum -- may not reflect the full impact of the debate.

"Only one-quarter of this sample is post-debate, so we'll have to wait a few more days to see," he said. "We'll have to look tomorrow to see if there was any McCain boost at all."    

Quick polls taken after Wednesday's debate judged Obama the victor, joining a string of surveys that show him ahead both in national polls and in most of the battleground states where the presidential election will be decided.

Obama, 47, has focused on the economy while on the campaign trail, appealing to voters buffeted by the global credit crisis and wild stock market swings on Wall Street.

McCain, 72, has sought to deliver his own economic message, along with aggressive attacks on Obama, but has failed to gain traction among crucial independent voters.

Obama held a 19-point lead in this group on Friday, up 5 points from Thursday's figures. "It would seem the independents are solidifying around Obama, which would be important," Zogby said.

Other national polls have given Obama a double-digit overall lead, although most have him in a range of 2 to 9 points ahead.

Both candidates continue to do well with their core supporters, with Obama winning nine of every 10 black voters and holding a 10-point lead among women voters.

McCain held a narrow 1-point lead among male voters and a larger 12-point lead among whites.  Independent Ralph Nader drew 2 percent support in the poll, while Libertarian Bob Barr got 1 percent, both unchanged from Thursday.

 The US president is determined not by the most votes nationally but by a majority of the Electoral College, which has 538 members allotted to all 50 states and the District of Columbia in proportion to their representation in Congress. - Reuters