RIGA, Latvia - As politicians and people worldwide marked the first anniversary of Russia's invasion of its neighbor on Friday, small sporadic protests broke out across Russia, where it is illegal to criticize the military or the conflict.

Antiwar memorials sprung up in support of Ukraine in Moscow and elsewhere, as police mounted a large presence in major cities to preempt unrest.

In Moscow, people brought flowers to the statue of a famed Ukrainian writer, Lesya Ukrainka, which became a makeshift memorial to Ukrainian victims of Russia's invasion following a missile strike on a residential building in Dnipro in January that killed at least 46 people.

In St. Petersburg, Russia's second-largest city, police detained several people as they tried to lay flowers near the statue of a 19th century Ukrainian poet, Taras Shevchenko, local media reported.

In Kazan, a regional capital on the Volga River, people brought flowers, toys and pictures of Ukrainian cities destroyed by the Russian army, to a monument commemorating victims of political repression.

Elsewhere, posters with the inscription "What's it all for?" or bearing expletive-ridden denunciations of the war were placed on top of rows of red carnations near a memorial in Khanty-Mansiysk, in western Siberia.

In Ivanovo, about 200 miles northeast of Moscow, activists put up a banner on the side of a highway overpass, which read "Enough of this bloody 'battle for peace.'"

In a more visual approach, in the city of Kaluga, southwest of Moscow, unknown protesters painted a large "Z" sign, a symbol of Russia's military, in yellow and blue - the colors of the Ukrainian flag.

Protests are virtually outlawed in Russia, and public opposition to the war poses great personal risks, including prosecution and long prison sentences, though pro-war hawks are generally permitted to complain that Russia is not winning fast enough, or to demand more brutal tactics. At least 19 people were detained across Russia on Friday, according to authorities.

When demonstrations broke out last year at the beginning of the invasion, Russian law enforcement cracked down, making nearly 20,000 arrests to show that public outcry would not be tolerated.

Russia on Friday had a national day off, an extension of Thursday's "Defender of the Fatherland Day" holiday to create a four-day weekend. Major cities were largely quiet, and there was scant official mention of the invasion anniversary - which Russia continues to call a "special military operation."

Overall, the Kremlin appears to prefer that Russians not dwell too much on the anniversary, Russia's military failures or the heavy human cost of the war in lost lives and destruction. State media focused mainly on international news.

Despite the pockets of protest, the Kremlin's effort to treat Russia's war on Ukraine as mere background noise in Moscow appeared mostly successful - at least on the surface. Billboards of Russian military figures are peppered along highways, and many citizens view the war as a distant conflict unfolding on television, with no major impact on their daily lives.

Moscuvites skate joyfully on the Red Square ice rink, as usual. Supermarkets and malls frequented by wealthy Muscovites are crammed with luxury goods, from Italian designer handbags to fresh sea bass flown in from Turkey. On Saturday nights, restaurants in the swanky Patriarch Ponds neighborhood are packed with staff turning hopeful patrons away.

Hundreds of Western companies left Russia in the aftermath of the invasion, but no one with money struggles too hard to get their hands on the Western brands they still crave.

So, the small pockets of antiwar protests in Russia stood out on Friday

Outside Russia, there were marches, demonstrations, vigils and other actions to condemn the war, some organized or attended by activist Russians abroad. Many of the protests were held outside Russian embassies.

"On this terrifying anniversary, Russians take to the streets and public squares of European, Asian, American . . . cities to demonstrate their solidarity with the Ukrainian people and to express their active rejection of the criminal war in Ukraine and the terrorist actions of the Kremlin regime," said a statement issued by one of the movement's disparate organizing groups.

Organizers of the global action said they were calling for the immediate cessation of hostilities and full withdrawal of troops from occupied regions of Ukraine, as well as a criminal tribunal for Russian President Vladimir Putin.

In London, Britain's King Charles III issued a statement lauding the "remarkable courage and resilience" of Ukrainians, who have "suffered unimaginably." Prime Minister Rishi Sunak led a minute of silence outside his Downing Street residence, while protesters painted a giant Ukrainian flag on the street outside the Russian Embassy, and authorities renamed a street in the capital as "Kyiv Road."

In Germany, activist groups rolled a wrecked Russian T-72 tank outside the Russian Embassy in Berlin, after it was destroyed during fighting in Kyiv last year, close to Bucha, organizers said in a statement. Germans lined up to take selfies and hold up Ukrainian flags near the Brandenburg Gate during an event to mark the anniversary of Russia's invasion.

In the Netherlands, the national anthem of Ukraine was playing on loop in front of the Russian Embassy in The Hague. In Belgrade, Serbia, a cake was left outside the Russian Embassy featuring a deathly skull.

Paris's Eiffel Tower lit up blue and yellow in solidarity, as did Sydney's iconic Opera House, while candlelight vigils took place in Japan and people in New Zealand threw sunflowers into water to show their support for Ukraine.

World leaders also issued a flurry of statements Friday condemning the Kremlin's war, among them French President Emmanuel Macron and Germany's Chancellor Olaf Scholz. The NATO military alliance condemned Russia's invasion as the "gravest threat to Euro-Atlantic security in decades" and called on Moscow to "engage constructively in credible negotiations with Ukraine."

The global solidarity comes a day after 141 countries voted to support a nonbinding resolution at the U.N. General Assembly on the eve of the anniversary Thursday, calling for an end to the war and demanding that Russia withdraw from Ukrainian territory. Some 32 countries, including Asian heavyweights China and India, abstained from voting. Seven countries, including Russia, voted against the resolution.

The Washington Post's Niha Masih contributed to this report. Ilyushina and Dixon reported from Riga; Suliman and Ebel reported from London.