Poland on Saturday reported a record of 1,002 new coronavirus cases, while neighbouring EU members Lithuania and Slovakia also logged their largest daily tallies since the pandemic began.
The Eastern European figures are in line with a surge in cases across Europe since August that has caused many countries to move back towards tougher restrictions.
"The numbers that we're seeing now are a result of people having returned to normal, everyday life, a return to work," Polish health ministry spokesman Wojciech Andrusiewicz said.
"It's what we're seeing in the streets everyday: more people, more contact," he told the Polish news agency PAP.
The increase brings the total of reported coronavirus cases in the nation of 38 million people to 78,330.
The ministry also reported Saturday 12 new COVID deaths, putting that total at close to 2,300.
In neighbouring Slovakia, a nation of 5.4 million people, the latest figure of 290 new infections brought its total to more than 6,500 cases.
"Now we have a new record. Today, the situation is becoming critical," Slovak Prime Minister Igor Matovic wrote on Facebook.
"However, if we remain responsible, we will live relatively freely despite the pandemic."
Lithuania, a Baltic state with a population of 2.8 million, reported its highest daily count as well.
The 99 new infections put the country's total at more than 3,600 cases.
The Czech Republic for its part reported more than 2,100 new cases, a day after registering a record of 3,130 new infections.
