The US has tallied the most new coronavirus cases in a week since a major summer outbreak, threatening to overwhelm hospitals in parts of the country just as voters head to the polls for one of the most hotly contested presidential elections in modern history.

The worst-hit region in the latest spike continued to be the Midwest, where some of the key battleground states in the presidential campaign posted record one-day increases in new infections on Friday. Those jumps pushed the nationwide tally to 83,010 new cases, according to the Covid Tracking Project, a record one-day rise.

Ohio, where President Donald Trump is clinging to a narrow lead in opinion polls, on Friday recorded its worst daily increase in new Covid-19 cases for the third day running, while Pennsylvania, a state regarded as key for the president’s re-election prospects, also reporting a single-day record.

Wisconsin, another key swing state where Democrat Joe Biden has been widening his lead, recorded its second-highest daily jump. Other states in the region that saw daily increases at or near records on Friday included Illinois, Indiana and South Dakota.

Over the course of the week, the US has seen 441,541 new cases, the biggest seven-day increase since the end of July.

Mr Biden has used the new outbreak to attack Mr Trump’s handling of the pandemic on the campaign trail. A day after warning of “a dark winter” ahead during a nationally televised debate, Mr Biden delivered an address accusing the president of “going on the offence for the virus” by downplaying the need for masks or social distancing measures.

“How many people . . . will end up suffering because their loved one listened to the president?” asked Mr Biden. “The longer Donald Trump is president, the more reckless he gets.”

Mr Trump continued to present a more optimistic picture, attacking Mr Biden for failing to give the American people hope that the pandemic would come to an end.

“He’s trying to scare people, basically,” Mr Trump said at a rally in central Florida. “We’re not entering a dark winter. We’re entering the final turn and approaching the light at the end of the tunnel.”

Much like previous coronavirus outbreaks, the recent spike in cases is producing increases in hospitalisations, with several regions reporting strains in their health systems. There are more than 41,000 people around the country currently in hospitals with coronavirus, the highest level in two months. Over the past week, 15 states have reported their highest level of hospitalisations of the pandemic.

In Texas, state health authorities reported on Friday that the number of people being treated for coronavirus in hospital had topped 5,000 for the first time in two months. The number of hospitalisations in New York surpassed 1,000 for the first time since late June.

The increases in states like New York and Texas, both of which suffered in earlier waves of the pandemic, are among the signs that the new spike, while centred in the Midwest and north, is beginning to grip regions across the country. California, a victim of the summer spike, reported its biggest one-day jump in coronavirus cases in two months on Friday.