A car has been driven into the gates of Angela Merkel's Federal Chancellery building in Berlin, German police say.
No casualties were reported and the background to the incident was unclear.
However, the car had messages daubed in white on both sides. One called for an end to "globalisation politics" while another referred to "you damned killers of children and old people"
Mrs Merkel is holding talks with regional leaders on Wednesday about extending Covid safety measures.
Germany's "lockdown light" is expected to be extended until 20 December.
Mrs Merkel will discuss a draft proposal agreed by the 16 state premiers to keep hotels and restaurants shut and limit private gatherings to five people (not including children under 14). A special Christmas exemption from 23 December to 1 January would allow gatherings of up to 10 people.
German health officials reported 410 deaths on Wednesday - the highest daily number since the pandemic began. However, Germany has seen proportionally far fewer fatalities than other Western European countries, with a total of 14,771.
Germany has a large protest movement against Covid-19 measures, including many anti-vaccination activists. Protesters rallied in the centre of Berlin last week close to the parliament building, the Reichstag, before the protest was broken up by police.
