U.S. President Barack Obama is warning of a “massive blow to the economy” if Congress fails to extend a payroll tax cut.

President Obama said it is time for Republican lawmakers to support his efforts to create jobs and extend tax cuts for the middle class. The president spoke at a high school Wednesday in the working-class town of Scranton, in the state of Pennsylvania.

He said the wealthiest Americans should pay what he called “their fair share,” while middle-class Americans should not have to pay more taxes during these difficult economic times.

He said if Congress fails to extend the tax cuts, middle-class Americans will see their taxes rise at the “worst possible time.” He said Congress can protect tax breaks for millionaires and billionaires, or cut taxes for middle-class Americans and those struggling to enter the middle class.

Republicans oppose raising taxes for the wealthiest Americans, saying that would hurt economic growth.