Angela Merkel has warned some German states that they are moving too quickly in lifting lockdown restrictions.
The German Chancellor said that the country was still "walking on thin ice" when it came to the coronavirus.
She said that the pandemic is "still at the beginning" before warning that some parts of Germany may be rushing their way out of lockdown.
Ms Merkel said the situation in the country is "fragile", despite Germany having kept its death toll to just over 5,000 while having the fifth highest number of confirmed coronavirus cases in the world.
At a joint press conference Christian Drosten, the director of the Institute for Virology at Berlin’s Charité hospital, said reopening shopping malls and larger stores could trigger a second wave in May and June.
He said Germany risked "gambling away" its early advantage ahead of the country's schools reopening on May 4.
Ms Merkel and state leaders are due to meet on April 30 to consider how to proceed after that.
She said: "We're not living in the final phase of the pandemic, but still at the beginning. We will be living with this virus for a long time."
The rate of new infections has been slowing but Mrs Merkel cautioned "we're still walking on thin ice, one could also say the thinnest ice".
She urged people to be cautious as steps were being taken to reduce restrictions, to avoid giving up hard-won gains.
"Let us not squander what we have achieved and risk a setback," Ms Merkel said.
"It would be a shame if premature hope ultimately punishes us all. Let us all stay on the path in the next phase of the pandemic: smart and careful. It's a long journey - we can't run out of stamina and air too soon."
She sympathised with people who wanted to end their isolation, especially among the elderly and disabled population.
Ms Merkel said: "In the times of a pandemic, it can be much lonelier without visitors.
"It is cruel when nobody can be there as strength fades and life comes to an end, aside from the nurses who are doing their very best.
"Let us never forget these people and the temporary isolation they have to live in. These 80- and 90-year-olds built our country; they are the foundation of the prosperity in which we now live.
"They are Germany, just like their children and grandchildren, and we also fight the fight against this virus for them."
