BERLIN — Chancellor Angela Merkel says there are promising signs that coronavirus infections are declining in Germany and that fewer people require intensive care. But she says Germany “has to take very seriously” the risk posed by a more contagious variant first detected in Britain.

Merkel and Germany’s 16 state governors on Tuesday decided to extend the country’s lockdown by two weeks until Feb. 14 and tighten some measures, for example requiring surgical masks — rather than just fabric face coverings — in shops and on public transport.

On Thursday, Germany’s disease control center said that 20,398 new cases were reported over the past 24 hours, nearly 5,000 fewer than a week ago. The number of new cases per 100,000 residents over seven days stood at 119, the lowest since the beginning of November — though still well above the level of 50 the government is targeting. There were 1,013 more deaths, bringing Germany’s total so far to 49,783.

Merkel said it’s important to prevent the new variant, which has been detected in Germany but isn’t yet dominant, from spreading. She pointed to the danger of a “third wave” of infections but said “there is still some time” to ward off that danger.