Kamala Harris embarked on a bus tour of the potentially election-deciding state of Pennsylvania on Sunday, as she keeps up the momentum before her star turn at the Democratic National Convention in Chicago. The US vice president has reenergized the party after an astonishing month that has seen her replace President Joe Biden at the top of the ticket and wipe out Republican rival Donald Trump's lead in the polls. Harris and her running mate Tim Walz, accompanied by their spouses, arrived at an airport hangar in Pittsburgh and greeted supporters, before setting off on a bus emblazoned with their names to a series of small towns to woo blue-collar voters.

Visiting a campaign phone bank later in Rochester, Pennsylvania, a crowd chanted "We are not going back" -- Harris's signature line as America's first female, Black and South Asian vice president casts herself as a new generation of leader. Her rapid rise has unsettled 78-year-old former president and convicted felon Trump, who is resorting to his favored tactic of personal insults as he struggles to recalibrate a campaign that had focused largely on 81-year-old Biden's age. A day earlier at a rally in Pennsylvania, Trump lashed out at Harris as a "lunatic" and bragged that he was "much better looking" than 59-year-old Harris.

The two campaigns are focusing heavily on Pennsylvania, in the heart of America's rust belt, which Trump won in 2016 before Biden seized it in 2020. Later in the day Harris will head to Chicago, where De.