The number of new confirmed coronavirus cases have spiked in several countries as Europe's first pandemic "travel bubble" burst and India's largest state recorded its millionth infection.
Health authorities in the Czech Republic, Ukraine and Hungary all reported record single-day numbers of COVID-19 cases on Friday while the UK registered its highest daily rate since May.
Hungarian Prime Minister Viktor Orban said his government was drafting a "war plan" to defend against the second wave of the pandemic.
The plan's aim was "not for everyone to stay at home and bring the country to a halt... but to defend Hungary's functionality," Orban said.
Orban reiterated the need to protect the elderly, one of the group's most at-risk during the pandemic, and authorities have banned most visits to retirement homes and hospitals to stem the spread of the virus.
Hungary reported 718 virus cases on Friday, 142 more than the country's previous 24-hour record.
The Czech Republic reported 1382 cases, which was about 200 more than its previous daily high and led to the return of face masks being mandatory in enclosed public spaces.
Coronavirus cases in the UK have risen to the highest level since mid-May.
The government said a total of 3539 new COVID-19 cases were recorded on Friday.
It is the highest daily figure since May 17 and Public Health England's medical director Professor Yvonne Doyle warned it is a reminder of the "ongoing risk as the virus spreads throughout the UK".
France is planning new restrictions to halt the spread of the virus in two major cities, Prime Minister Jean Castex said on Friday after infections hit a record daily high.
Castex warned that "for the first time in many weeks," the number of patients hospitalised was also going up and the virus was again beginning to infect elderly and other vulnerable people.
French health authorities said late on Thursday that 9843 new cases had been diagnosed in the previous 24 hours.
That is higher than was recorded during the March-to-April peak of the virus that resulted in more than 24,000 deaths.
France's total death toll now stands at more than 30,800.
The European pandemic "travel bubble" created in May by Estonia, Latvia and Lithuania ended on Friday as Latvia said it was mandating a 14-day quarantine on everyone arriving from Estonia.
Estonia has had 21 coronavirus infections per 100,000 population over the previous two weeks, according to the European Centre for Disease Prevention and Control, passing the 16 threshold set by Latvia for mandatory quarantine.
Latvia, which has one of the lowest levels of infection in the European Union, has rejected the European Commission's recommendation to raise threshold for quarantine to 25 new cases per 100,000 population over two weeks.
"This is a decision I am not ready for... I do not think that society is ready to allow more people to enter Latvia," Prime Minister Krisjanis Karins said on Friday.
Neighbouring Estonia, Lithuania and Finland all raised the threshold this week, keeping travel between them possible.
India's biggest and richest state, Maharashtra, recorded its millionth infection on Friday, putting it on par with Russia in the pandemic.
Cases in the western state, home to financial capital Mumbai, passed 1 million as infections have been rising about 20,000 a day recently.
If it were a country, the state would now rival Russia for the fourth-highest caseload globally.
The rise in the state of 130 million people has propelled India's COVID-19 surge, accounting for nearly one-quarter of the country's total.
India's health ministry registered 96,551 new confirmed cases on Friday, taking the tally to more than 4.56 million, and recorded another 1209 deaths for a total of 76,271.
India is likely to hit 5 million cases in coming days, behind only to the United States.
The global death toll from the coronavirus passed 900,000 on Wednesday as worldwide cases topped 27.7 million.