The global coronavirus death toll could hit two million before an effective vaccine is widely used, the World Health Organization (WHO) has warned, BBC reports.
Dr. Mike Ryan, the WHO's emergency head, said the figure could be higher without concerted international action.
The start of the second surge of coronavirus infections has been seen in many countries in the northern hemisphere as winter approaches.
So far, the US, India, and Brazil have confirmed the most cases, recording more than 15 million between them.
There has been a resurgence of infections across Europe, prompting warnings of national lockdowns similar to those imposed at the height of the first wave of the pandemic.
"Overall within that vast region, we see worrying increases of the disease," Dr. Ryan said of the marked spike in cases in Europe.
He urged Europeans to ask themselves whether they had done enough to avoid the need for lockdowns - and whether alternatives, such as testing and tracing, quarantines, and social distancing, had been implemented.
"Lockdowns are almost a last resort - and to think that we're back in the last-resort territory in September, that's a pretty sobering thought," Dr. Ryan told reporters.