WASHINGTON (AP) — Republican Sen. John McCain has erased Sen. Barack Obama's 10-point advantage in a head-to-head matchup, leaving him essentially tied with both Democratic candidates in an Associated Press-Ipsos national poll released Thursday.

The survey showed the extended Democratic primary campaign creating divisions among supporters of Obama and rival Sen. Hillary Rodham Clinton and suggests a tight race for the presidency in November no matter which Democrat becomes the nominee.

McCain is benefiting from a bounce since he clinched the GOP nomination a month ago. The four-term Arizona senator has moved up in matchups with each of the Democratic candidates, particularly Obama.

An AP-Ipsos poll taken in late February had Obama leading McCain 51-41 percent. The current survey, conducted April 7-9, had them at 45 percent each. McCain leads Obama among men, whites, Southerners, married women and independents.

Clinton led McCain, 48-43 percent, in February. The latest survey showed the New York senator with 48 percent support to McCain's 45 percent. Factoring in the poll's margin of error of 3.1 percentage points, Clinton and McCain are statistically tied.