WILMINGTON, Del. — Presumptive democratic nominee Joe Biden called for a nationwide mask mandate at an event Thursday, citing his team of health experts saying such a ban could save "over 40,000 lives."

"Every single American should be wearing a mask when they're outside for the next three months, at a minimum — every governor should mandate mandatory mask wearing," Biden said.

”Wearing the mask is less about you contracting the virus,” Biden added. “It’s about preventing other people from getting sick.”

The former Vice President also responded to those who push back against such mandates: “This is America. Be a patriot. Protect your fellow citizens. Step up, do the right thing.”

President Donald Trump on Wednesday said at a press briefing that his administration was sending 125 million reusable masks to school districts across the nation.

Trump has urged Americans to wear masks but has opposed the idea of a national requirement and declined to wear one for months. He has worn one on occasion more recently.

On Thursday he again dismissed critics who say he was too slow to react to the pandemic in the U.S., saying on Fox Business Network that “nobody blames me.”

“Look, we got hit by the China plague and we’re not going to forget it. We got hit by the China plague,” he said.

On Wednesday, when the U.S. reported 1,499 new coronavirus deaths, the highest number of COVID-19 deaths in a single day since May, Trump pushed for schools and businesses to continue opening, and called for college football to go on despite several leading leagues' leaders deciding to cancel this year’s season.

Biden and running mate California Sen. Kamala Harris spoke briefly Thursday in the same Wilmington hotel ballroom where they held a virtual fundraiser after appearing together as running mates for the first time Wednesday. They were briefed by public health and economic experts on the coronavirus pandemic, which has caused the deaths of more than 166,000 Americans and plunged the global economy into the worst economic recession since World War II.

The Associated Press contributed to this report.