Lothar Wieler said despite Germany's ''success in the last few weeks to stabilize infection numbers," cases in the country "remain too high."
We have reached a plateau but infection numbers are not decreasing just yet," he added.
Wieler went on to say that Germany's ''death toll is rising from week to week'' and ''in some regions, hospitals are on the brink."
Particularly worrying is the spread of coronavirus infections in care homes where, according to Wieler, many elderly patients over 80 are at risk. ''We must protect the elderly," he said, pointing to statistics that show ''every fifth person with Covid-19 in care homes is at risk of dying.''
The head of RKI's surveillance unit, Ute Rexroth, warned that the virus is circulating at particularly high levels between the age group of 15 to 29, and is being spread to the elderly generation. "The incident rate must be brought down," he said.
Germany's Chancellor Angela Merkel on Wednesday said that ''the goal continues to be to get the incidence numbers below 50 cases per 100,000 inhabitants for seven days."
"We have a very high daily number of fatalities and this shows us once again just how big a responsibility we have to get the incidence rate below 50 again," Merkel said.
On Thursday, Germany recorded 22,046 new coronavirus infections, bringing the total tally to 1,106,789, according to RKI data. The reported death toll rose by 479 to 17,602.