PHOENIX - Arizona Gov. Doug Ducey blasted Joe Biden's proposed COVID-19 vaccine requirements, vowing Thursday to “push back” against the policy before the president even officially announced it.

"This is exactly the kind of big government overreach we have tried so hard to prevent in Arizona — now the Biden-Harris administration is hammering down on private businesses and individual freedoms in an unprecedented and dangerous way," Ducey, a Republican and frequent critic of the nation’s Democratic executive branch, tweeted after media outlets reported details of the plan. "This will never stand up in court."

Less than an hour after Ducey expressed his displeasure, Biden officially revealed the new requirements affecting as many as 100 million Americans in an effort to increase COVID-19 vaccinations and curb the surging delta variant that is killing thousands each week and jeopardizing the nation's economic recovery.

The new rules mandate that all employers with more than 100 workers require them to be vaccinated or test for the virus weekly, affecting about 80 million Americans. And the roughly 17 million workers at health facilities that receive federal Medicare or Medicaid also will have to be fully vaccinated.

"This dictatorial approach is wrong, un-American and will do far more harm than good," Ducey tweeted. "How many workers will be displaced? How many kids kept out of classrooms? How many businesses fined? The vaccine is and should be a choice.

"We must and will push back."

Biden also planned to issue an executive order to require vaccination for employees of the executive branch and contractors who do business with the federal government — with no option to test out. That covers several million more workers.

The president announced the new requirements in an address from the White House as part of a six-pronged action plan to address the latest rise in coronavirus cases and the stagnating pace of COVID-19 shots that has raised doubts among the public over his handling of the pandemic.

Tune to KTAR News 92.3 FM, our app or online for live coverage of Biden’s address and reaction to the plan.

The Associated Press contributed to this report.