Berlin: More than 100,000 people protested in solidarity with Ukraine in Berlin on Sunday, calling for the end of Russia's invasion and saying history should not repeat itself.

Train and underground service was interrupted in some parts of the German capital as thousands made their way to the Brandenburg Gate in central Berlin, near the Russian embassy.

The crowd of protesters bearing signs reading: "Stop the War", "Putin's last war" and "We stand with Ukraine" along with Ukrainian and European Union flags, extended from the Victory Column in the heart of the capital.

The protest comes as Russia's attack on Ukraine entered its fourth day, triggering three sanctions package from Germany and its Western allies and pushing Berlin to shift its decades-long policy of not exporting arms to conflict zones.

"Ukrainians: You're welcome here!" shouted one of the speakers as the crowd cheered.

The police had expected some 20,000 people to participate in the protest but estimated that the number of people who have taken part is a "six-digit figure", adding that more people were still flocking to the demonstration.