Protesters turned out in cities around the world on Thursday in solidarity with Ukraine against Russian President Vladimir Putin's "surreal war", as hundreds of demonstrators who marched in Russia itself were arrested.

Police made more than 1,700 arrests in 51 cities across Russia, an independent monitor said, cracking down on dissent after authorities warned citizens against marching.

Demonstrators gathered in Berlin to protest against Russia's invasion of the Ukraine
Demonstrators gathered in Berlin to protest against Russia's invasion of the Ukraine AFP / John MACDOUGALL

In Berlin, several hundred people rallied at the Brandenburg Gate, lit up in the blue and yellow colours of the Ukraine flag for the second evening.

Anton Kushch, 35, a Ukrainian software engineer, said he woke up to "a push notification on my phone about war" and had been sent "messages on my phone with all these burning tanks on the roads".

"It's hard to believe, it's surreal," he said. "This is just catastrophic for the whole world... But we have what we have, a tyrant sitting there in the Kremlin."

Pro-Ukrainian protesters took to the "Promenade des Anglais" at the French Riviera city of Nice
Pro-Ukrainian protesters took to the "Promenade des Anglais" at the French Riviera city of Nice AFP / Valery HACHE

Student Sofia Avdeeva, 22, from the disputed Donetsk region, described Putin as a "war criminal" and said she hoped "the same thing he is putting people through happens to him and his family".

Russians also joined the protests, with some holding placards outside the Russian embassy.

"We want to show that we are against the war," said Ekaterina Studnitzky, 40, a teacher from Moscow, holding a cardboard Ukraine flag.

Ukranians living in Beirut demonstrated outside the Russian Embassy
Ukranians living in Beirut demonstrated outside the Russian Embassy AFP / JOSEPH EID

"Ukraine was always a very friendly and close country to us. We have a lot of relatives there, a lot of friends. Nobody wants this war," she said.

Around 150 demonstrated in Stockholm outside the Russian embassy, waving Ukrainian flags
Around 150 demonstrated in Stockholm outside the Russian embassy, waving Ukrainian flags TT NEWS AGENCY via AFP / Claudio BRESCIANI

"This is just terrible. Ukrainian and Russian people are brothers and sisters," said Olga Krupacina, 32, a student from Kaliningrad.

Thousands rallied on Prague's Wenceslas Square then marched toward the Russian embassy, with demonstrators carrying a large poster featuring Hitler and Putin and the tagline 1938-2022, referring to the year of Nazi Germany's occupation of Czechoslovakia.

Protesters shouted "Pack up your bags!" and "Glory to Ukraine, glory to the heroes!"

Ukrainians living in Beirut demonstrated outside the Russian embassy
Ukrainians living in Beirut demonstrated outside the Russian embassy AFP / JOSEPH EID

In Paris, several hundred people gathered outside the Russian embassy.

Protesters chanted "Stop Putin, stop the war" and carried placards with slogans declaring "No war" and "Putin Ukraine 2022, Hitler Poland 1939".

"We are here to support the people of Ukraine, those who are still there," said French-Ukrainian protester Teresa Voytanovska, 42.

Amsterdam's Dam Square also saw protesters show their support for Ukraine
Amsterdam's Dam Square also saw protesters show their support for Ukraine ANP via AFP / Sem van der Wal

In New York, around 200 protesters marched from Times Square to Russia's UN office. Among them was 34-year-old Kateryna Bieliaieva.

"I feel so powerless, this is the only thing I could do. I want to do more," she told AFP.

In Madrid, Oscar-winning Spanish actor Javier Bardem was among roughly 50 people who gathered outside the Russian embassy.

He told a local television station he was protesting Putin's "absurd, cruel and voracious attack" on Ukraine, describing the Russian leader as an "ultranationalist".

In London, a few hundred mainly Ukrainian protesters rallied outside Prime Minister Boris Johnson's official Downing Street residence, which was lit up yellow and blue.

"Wake up, Russia, wake up!" the crowd chanted, many of them tearful.

Around 150 people demonstrated in Stockholm outside the Russian embassy, waving Ukrainian flags and holding signs reading "Ukraine, solidarity!", "Stop Russian aggression" and "Stop the bloody maniac".

"We feel destroyed... It's a very bad feeling when your mum calls you at six o'clock in the morning and says that the war has started," said Yevhenii Osypchuk, a 27-year-old car mechanic.

"So we just decided to leave our jobs and to come to say 'no' in front of the Russian embassy."

In the Netherlands, about 100 pro-Ukrainian protesters gathered in front of the Russian embassy in The Hague and a similar number demonstrated on Amsterdam's Dam Square, Dutch public broadcaster NOS reported.

Images showed many people draped in Ukrainian flags, carrying placards saying "No war" and chanting "Putin is a killer".

In Dublin on Thursday morning, a small group of protesters gathered outside the Russian embassy where red paint was splattered on the mission's emblem by a gated entrance.

Later in the day, dozens of protesters gathered outside the national parliament building in the centre of the Irish capital carrying Ukrainian flags and placards emblazoned with "stand with Ukraine" and "Putin get out of Ukraine".

In Georgia, thousands rallied in the capital Tbilisi's main thoroughfare, waving Ukrainian and Georgian flags and holding banners that read "Putin get out of Ukraine".

The war has sparked a sense of deja vu in Georgia, which faced a devastating Russian invasion in 2008.