President Donald Trump has wrapped up the first of three campaign rallies in Pennsylvania, where he told supporters that he wanted to discuss an issue of "existential importance" as he focuses on former Vice-President Joe Biden's policies on energy.

Pennsylvania is the second leading producer of natural gas in the country behind Texas.

Trump claims that Biden would "abolish the entire U.S. oil industry."

Trump says that means no fracking and no jobs for Pennsylvania families, adding "Biden's plan is an economic death sentence for Pennsylvania's energy sector."

He is seizing on Biden's comments in last week's debate that he would "transition away from the oil industry."

But Biden sought to clarify later that he was talking about ending federal subsidies for oil companies.

He also said "we're not getting rid of fossil fuels for a long time."

Biden has also repeatedly pledged not to abolish fracking.

Instead, he has called for no new fracking permits on federal lands.

Melania Trump is set to make appearance for President Donald Trump

Melania Trump is set to make her first solo campaign-trail appearance of 2020 for President Donald Trump.

Trump's reelection campaign says the first lady will appear at an event Tuesday in Atglen, Pennsylvania, that will be moderated by former White House counsellor Kellyanne Conway.

The campaign says she will share the president's agenda with Pennsylvanians.

The first lady has not appeared at one of the president's campaign events since June 2019 in Orlando, Florida, where the president formally announced his bid for a second term.

She had been scheduled to headline campaign fundraisers back in March, but those events were cancelled due to the coronavirus outbreak.

Mrs. Trump recently recovered from a bout with COVID-19, the disease caused by the novel coronavirus.