Worldwide coronavirus cases crossed 40 million on Monday, according to a Reuters tally, as the onset of winter in the northern hemisphere fuelled a resurgence in the spread of the disease.

The Reuters tally is based on official reporting by individual countries. Experts believe the true numbers of both cases and deaths are likely much higher, given deficiencies in testing and potential under-reporting by some countries.

The Reuters data shows the pace of the pandemic continues to pick up. It took just 32 days to go from 30 million global cases to 40 million, compared with the 38 days it took to get from 20 to 30 million, the 44 days between 10 and 20 million, and the three months it took to reach 10 million cases from when the first cases were reported in Wuhan, China, in early January.

Record one-day increases in new infections were seen at the end of last week, with global coronavirus cases rising above 400,000 for the first time.

There were an average of around 347,000 cases each day over the past week, compared with 292,000 in the first week of October.

The United States, India, and Brazil remain the worst affected countries in the world. COVID-19 cases in North, Central, and South America represent about 47.27% or nearly half of global cases.

Around 247 cases are seen per 10,000 people in the United States. For India and Brazil, those numbers stand at 55 cases and 248 cases per 10,000 people respectively.

New cases are growing at over 150,000 a day in Europe, as many countries including Italy, Netherlands, Germany, Austria, Poland, Ukraine, Cyprus, and the Czech Republic have reported record daily increases in the number of coronavirus infections.

Europe currently accounts for over 17% of the global cases and nearly 22% of the deaths related to the virus worldwide.

Parts of the UK were put into lockdown as Prime Minister Boris Johnson bid to contain a second wave of infections through local measures.

France imposed curfews while other European nations are closing schools, canceling surgeries, and enlisting student medics.

President Donald Trump called for a big economic stimulus as U.S. infections surpassed eight million, with record spikes in several states.

States across the Midwest are seeing a rise in coronavirus cases, with new infections and hospitalizations rising to record levels.

India's cumulative tally of coronavirus infections stood at 7.43 million on Saturday, with the number of active infections slipping below 800,000 for the first time in 1.5 months.

Iran, the Middle Eastern country hardest-hit by the coronavirus, extended restrictions and closures in the capital Tehran into a third week on Saturday as its death toll rose above 30,000.

Since the pandemic started, over 1.1 million people have died due to COVID-19, with the global fatality rate hovering around 2.8% of the total cases.

An official at the World Health Organization has said the global death toll from COVID-19 could double to 2 million before a successful vaccine is widely used and could be even higher without concerted action to curb the pandemic.