The World Health Organization (WHO) has warned that coronavirus cases are surging alarmingly in Europe, as a "very serious situation" unfolds across the continent.

As Covid-19 infections spike to record numbers, European governments are imposing strict local measures and weighing up further lockdowns in a bid to halt a second wave of the pandemic.

But WHO regional director Hans Kluge said at a Thursday news conference that the increase in cases should serve as a warning of what is to come.

"Weekly cases have now exceeded those reported when the pandemic first peaked in Europe in March," Kluge said. "Last week, the region's weekly tally exceeded 300,000 patients."

More than half of European nations have reported an increase of more than 10% in new cases in the past two weeks, Kluge added. "Of those, seven countries have seen newly reported cases increase more than two-fold in the same period," he said.