The U.S. presidential candidates are wooing voters in key battleground states with their new running mates after an historic week in U.S. politics.

Sen. John McCain (l) smiles as his Vice Presidential running mate, Alaska Gov. Sarah Palin, pumps her fist at a campaign rally in Dayton, Ohio, 29 Aug 2008

Republican candidate, Senator John McCain will campaign in the city of Washington, in the eastern state of Pennsylvania Saturday night with running mate, Alaska Governor Sarah Palin.  McCain selected the relatively unknown Palin on Friday, making her the first female presidential running mate on the Republican ticket.

Democratic nominee Barack Obama on Thursday became the first African-American to lead a major party ticket.  Senator Obama is on a bus tour with running mate, Delaware Senator Joe Biden. The pair will hold a rally Saturday night in the city of Dublin in the state of Ohio.

The Gallup polling firm says Obama's lead over his Republican rival grew from a tie to eight percentage points following the four-day Democratic National Convention.

The Republican National Convention is set to begin next week in St. Paul, in the northern state of Minnesota.