LONDON — The exponential surge of coronavirus cases across Europe has warranted the restrictive measures being taken in numerous countries, making them “absolutely necessary,” the head of the World Health Organization’s Europe office says.

In a press briefing Thursday, Dr. Hans Kluge warned that even more drastic steps could be taken if the pandemic does not recede.

He called for countries to be “uncompromising” in their attempts to control the virus and said most of the COVID-19 spread is happening in homes, indoor spaces and communities not complying with protection measures.

“These measures are meant to keep us all ahead of the curve and to flatten its course,” Kluge said, while wearing a mask. “It is therefore up to us to accept them while they are still relatively easy to follow.”

Kluge cited epidemiological models that suggested if 95% of people wear masks and other social distancing measures are applied, Europe could avoid about 281,000 deaths by February. But he warned that relaxing measures could lead to a five-fold increase in deaths by January.

“The evolving epidemic in Europe raises great concern,” he said. “But we should not hold back with relatively smaller actions in order to avoid the same very painful damaging actions we saw in the first peak.”