@ioffeinmoscow/Twitter

MOSCOW - As a bloody skirmish between police and opposition activists in central Moscow was drawing to a close on Sunday a small boy on a tiny bicycle pedaled through the crowd and approached a line of hulking riot police.

He sat there for a moment, balancing on his training wheels, staring at the menacing troops who were decked out in blue camouflage uniforms and full riot gear, nightsticks at the ready.

A group of protesters who had been heckling the cops began jeering, "Here's the guy that will storm the Kremlin. Be ready boys! Here he comes!"

Julia Ioffe, the Moscow correspondent for The New Yorker and Foreign Policy magazine, happened to be standing right behind him. She whipped out her iPhone and snapped a picture which she tweeted out to her over 6,000 followers with the caption "Russia's Tianamen (sic) image."

The photo quickly ricocheted around the internet.

It was a David and Goliath moment, perhaps a metaphor for the unarmed protesters who clashed with police that day and whose movement is taking on President Vladimir Putin's formidable political system.

Tens of thousands of protesters had marched against Putin that afternoon, the day before his inauguration. They were met by row after row of police, thousands of them, who were there to make sure they stayed within the bounds of their rally permit.

When a large group tried to cross a police line towards the Kremlin, police pushed them back and tensions flared. Rocks and bottles were thrown and police responded with what many say was disproportionate force,  deploying tear gas and striking people with their batons. They surged into the crowd to grab individuals and drag them by their arms, legs, and even their hair back to police vans. Many protesters were bloodied. By the end of the day more than 450 people had been arrested.

Ioffe had been there all day to cover the protest. She was in the thick of the melee and says she was  struck in the leg by a rock. When police had finally cleared the square, only a handful of protesters remained behind, including the group heckling the riot police.

"Shame on you," they shouted. "What are you going to tell your grandparents who fought against the fascists? Don't you have mothers?"

Ioffe says she was walking with another journalist, Olaf Koens, who works for RTL Television in the Netherlands. They were tired and wanted to go find some dinner when they stopped to watch.

Koens spotted the boy first.

"Olaf smacked me in the arm and said look at that," she recalled later when ABC News asked about the photo. "Then I see this little bicycle weave through the crowd and stop in front of the troops. He stood there for a few minutes. I'm not sure why."

Koens says he wanted to take the picture himself, but his iPhone battery had run out an hour earlier.

"This little boy just showed up. His parents were somewhere in the crowd, there was no immediate danger, and the kid just kind of peddled (sic) up to the police, probably out of curiosity," he wrote in an email to ABC News.

Ioffe laughed at the thought that one of her pictures has gone viral and is being called iconic.

"I didn't think it would be any good. I'm a terrible photographer, especially with an iPhone," she said, adding that her family usually won't even let her take pictures on vacation.

Maybe now they will.