PHILADELPHIA — Hillary Clinton and running mate Sen. Timothy M. Kaine (Va.) will campaign alongside former president Bill Clinton in Philadelphia on Friday, the day after she claims the Democratic presidential nomination.

Her campaign announced Monday that the Democrats will hold a rally on Independence Mall immediately before Clinton and Kaine embark on a bus tour through Pennsylvania and Ohio — two key swing states where the competition with Republican Donald Trump is expected to be fierce — focusing on Clinton’s economic platform.

The Rust Belt — parts of Western Pennsylvania and Ohio — could be where Donald Trump’s message resonates most with white, working-class voters. Clinton intends to take the bus tour to some of the more Republican corners of the state, where they will probably find voters amenable to Trump's message.

The choice of venue is an acknowledgment by the Clinton campaign that they believe Trump will stake his electoral success on his strength with working-class voters in economically hard-hit communities. Clinton and Kaine will hold rallies and local retail stops focused on the economy.

The swing will be just the second time that Clinton and Kaine have campaigned together since he was selected as her running mate.

After the rally in Philadelphia on Friday, they will travel throughout the state, including to Harrisburg and Pittsburgh. On Saturday, the bus tour will reach Ohio, where they will travel to Youngstown and Columbus.

Kaine, a Midwestern-raised former mayor and governor of a Southern swing state, is a less-familiar political figure than Clinton but one who is known for his more folksy campaign style.

That could help Clinton who is sharply disliked and mistrusted by a wide swath of voters, polling shows.

In a recent ABC News/Washington Post poll, 54 percent of voters viewed Clinton unfavorably. Trump fares worse, however, with 64 percent viewing him unfavorably.

Anne Gearan contributed to this report.