A recent increase in the weekly number of new coronavirus cases in Europe was a reminder not to be complacent, the head of the World Health Organization's (WHO) European regional office said on Thursday.

"Last week, Europe saw an increase in weekly cases for the first time in months," Hans Kluge of the Copenhagen-based agency said, noting 30 countries had increased over the past two weeks.

At a weekly online briefing, Kluge said that while the WHO European Region has reported "a decreasing proportion of global cases than earlier in the year, the region continues to report close to 20,000 new cases and over 700 new deaths daily."

The WHO European region groups 53 countries. They have had about 2.5 million cases in total.

"We are still in the first wave (of infection) in many countries," he said, adding there was a need to prepare for the autumn period since the virus was "actively circulating."

Kluge praised "rapid and targeted" responses by Poland, Germany, Spain and Israel following recent "dangerous outbreaks of COVID-19 associated with schools, coal mines and food production settings."

The health agency head also highlighted how digital technology can be used for contact tracing as part of measures to tackle the virus and reduce transmissions, noting solutions used in 27 countries including Austria, Georgia and North Macedonia.

However, the use of digital technologies "must consider the privacy and security of individuals and their data," Kluge said.