Seeking to boost their chances in the critical Philadelphia suburbs, Donald Trump and Gov. Mike Pence used a campaign stop in King of Prussia on Tuesday to denounce the Affordable Care Act and for the first time offer specifics on a health-care alternative under a Trump presidency.

The Republican candidate presented his plan to 700 invited guests at the DoubleTree hotel, saying it would repeal and replace President Obama's health-care law, one he said has "devastated" people with health-care costs "that are more than their mortgages or rent."

"Insurers are leaving, premiums are soaring, doctors are quitting, companies are fleeing, and deductibles are through the roof," Trump said. "Obamacare means higher prices, fewer choices, and lower quality."

Since launching his campaign, Trump has repeatedly lambasted the Affordable Care Act but offered few details on his own plan, using the controversial law as a strategy to attack Democratic nominee Hillary Clinton, who supports it but has vowed to make changes.

But after the Obama administration said last week that the cost of midlevel plans will increase by an average of 25 percent across 39 states in 2017, Trump and his running mate finally offered their alternative. Many of those increases, however, will be mitigated by government subsidies expected to rise alongside premiums.

Similar to past proposals floated by GOP leaders, Trump's plan would discard individual mandates and penalties, one of the central provisions of Obamacare upheld by the U.S. Supreme Court.

"Government should not tell you how to spend your money and put priorities in your life," Pence said, stirring applause and cheers from the crowd.

A week after Trump had stumbled while discussing Obamacare at a Florida rally - declaring that many of his employees at a Miami golf course were having "tremendous" problems with Obamacare, when most were privately insured - the campaign let Pence do most of the talking about health care Tuesday.

A Trump administration, the Indiana governor said, would expand health savings accounts - the tax-exempt funds for healthcare expenses permitted in some capacities under Obamacare. In a more detailed platform on the Trump website posted later Tuesday, the campaign also explained that individuals would be able to deduct health-insurance premium payments from their tax returns.

In addition, he said, Trump's plan would allow Americans to purchase insurance across state lines and allow states to manage their own Medicaid funding.

How quickly a Trump administration could repeal Obamacare remains unclear and could largely depend on Republicans' success down-ballot races.

Still, Trump boasted that upon taking office, he would immediately "ask Congress to convene a special session so we can repeal and replace," before quickly moving to his usual stump speech, promising to bolster the military and return manufacturing jobs to Pennsylvania.

Beyond Pence, the event also drew other Republican officeholders and supporters Tuesday, including former presidential candidate Ben Carson and U.S. senators and representatives with backgrounds in health and medicine.

"We are going to bring the power back to the people and the health-care providers," Carson said. " In Washington ... they will learn what the words 'you're fired' mean."

A new Franklin and Marshall poll of voters Tuesday showed Trump trailing Clinton in the Keystone State by 11 points, one of the largest margins this fall. But other polls this week have suggested the race is closer.