A massive crowd gathered in the German capital to protest Russia's invasion of Ukraine while the German parliament is holding a special session.

At least 100,000 people gathered in the center of Berlin to demonstrate against Russia's invasion of Ukraine as the German parliament was in an extraordinary session over the response to the resulting security crisis.

Greenpeace Germany placed the number of those in attendance at 500,000 where Berlin police said a fraction of that number had gathered, estimating the crowd size "at least a low six-number figure."

Many of those in attendance dressed in the sunflower yellow and sky blue of the Ukrainian flag. They carried signs that said, "No World War 3" and "Stop the killer" as they amassed at the Brandenburg Gate, located near the Russian Embassy on Under den Linden street in central Berlin.

Hans Georg Kieler, 49, who attended the demonstration said: "It is important to me for Germany to show that it is standing for democracy in Europe."

Ukrainian Valeria Moiseeva, 35, said her mother was afraid as she sits in a bomb shelter in Kyiv. She said she attended the protest because "I can't do more than that."