British Prime Minister Boris Johnson has said he is cautious about rising cases of Covid-19 in Europe, warning of gathering "storm clouds" of a new wave of coronavirus infections, reports Reuters.

Infection rates in Britain are coming down just as they are rising sharply in other European countries, such as Germany, Austria and the Netherlands.

Parts of Eastern Europe have also seen a sharp rise in cases.

"I'm seeing the storm clouds gathering over parts of the European continent. And I've got to be absolutely frank with people: we've been here before. We remember what happens when the wave starts rolling in," Johnson said, referring to previous waves of infections.