Last Updated, 6:50 p.m. | As the deadly clashes in the Ukrainian capital, Kiev, continued late Tuesday, hundreds of thousands of people followed the violence as it unfolded, watching a live YouTube video stream from the besieged protest camp provided by the local website Espreso.tv, and reading Twitter updates from reporters and activists in Independence Square.

Truly nightmarish scene on Maidan. Fires raging all around, police showering protesters with rubber & live ammo, bloody faces everywhere. — Christopher Miller (@ChristopherJM) 18 Feb 14

Even as the death toll moved into double figures, the blogger Vitaliy Umanets posted a brief clip on YouTube showing the defiant mood in the square at 11 p.m. local time.

Tens of thousands more viewed a second live video stream from the square posted on YouTube by Radio Svoboda, an American-financed broadcaster. As Myroslava Petsa, a correspondent for Ukraine’s Channel 5, noted, even though the independent station was forced off the air across the country, it has also continued to stream live coverage of the crisis on YouTube.

One antigovernment activist, Kateryna Kruk, reported that the riot police, known as the Berkut, were slowly edging into the square protesters have rechristened Euromaidan, or Europe Square, to mark their defiance of President Viktor Yanukovych’s decision to reject an economic pact with the European Union in favor of closer ties to Russia.

very slowly but berkut is comming inside #euromaidan ….they use water cannons as a shield and move behind it — Kateryna_Kruk (@Kateryna_Kruk) 18 Feb 14

writing tweets about #euromaidan ‘s crackdown is a torture for me.if only this was just a bad dream! — Kateryna_Kruk (@Kateryna_Kruk) 18 Feb 14

right now on #euromaidan – @okeanelzy ‘s song I WON’T GIVE UP WITHOUT A FIGHT,anthem of maidan! — Kateryna_Kruk (@Kateryna_Kruk) 18 Feb 14

As midnight approached in Kiev though, Uliana Kovalchuk, a 19-year-old student activist at the University of Lviv, shared footage of protesters continuing to hold the central square as fires burned and rock music blared from the protest camp’s sound system.

At 1 a.m. Instagram video shared by Mustafa Nayyem, an Afghan-Ukrainian journalist in the square, showed the demonstrators still entrenched, and a protester hurling a flaming Molotov cocktail at the police with one hand while clinging tightly to his phone with the other.

A longer view of the square could be seen in video streamed late Tuesday by the blogger Lyalya Horsky.

Ustream video from another camera, positioned above a distinctive colonnade on nearby Hrushevskoho Street, appeared to show the authorities engaged in frantic clean-up work on a piece of ground they reoccupied Tuesday, erasing the signs of a weeks-long occupation by protesters.

In a recorded video clip posted on YouTube, Radio Svoboda documented the deadly cost of the police action on Tuesday, with graphic images of the dead bodies of two protesters.

A dead or unconscious officer’s limp body could also be seen at one point in video of intense clashes earlier in the day on Shovkovychna Street in Kiev posted online by the Ukrainian affiliate of the congressionally financed Radio Free Europe/Radio Liberty network.

Video posted on YouTube late Tuesday by bloggers describing themselves as part of an antigovernment “self-defense” group, from the ultranationalist Right Sector, appeared to show, from two angles, a police armored vehicle being engulfed in flames as it drove towards a barricade and demonstrators hurled Molotov cocktails.

Another clip, posted on Facebook by Sergii Morgunov, a Ukrainian video blogger, appeared to show a protester being shot on astreet near the square.

Amid the chaos on the streets Tuesday night, a supporter of the protest movement named Volodymyr Horbach posted video on Facebook of the United States Ambassador to Ukraine, Geoffrey Pyatt, briefly stepping into the law and order void by personally directing traffic, as he attempted to make his way to meetings in another part of town.

Mr. Pyatt confirmed that it was him in response to questions on Twitter.

@OdessaBlogger totally self interested. Trying to get downtown where the work is. — Geoffrey Pyatt (@GeoffPyatt) 18 Feb 14

Last week, Mr. Horbach shared “I Am a Ukrainian,” an English-language YouTube video made to explain the protest movement to non-Ukrainians and drum up support from abroad.

This generation of young Ukrainian. They are the newest Europeans. //t.co/kzIjRpN2mP — Volodymyr Horbach (@horbachvolod) 13 Feb 14

Earlier in the day, Christopher Miller of the English-language Kyiv Post reported, protesters could be seen jeerign and waving money at so-called “titushki,” a derisive name for thugs paid to support the government, near Mariinsky Park in Kiev.

Mr. Miller also reported that some of the riot police officers freely admitted that they were enjoying the street fighting.

Behind police lines w/ Berkut, I watched 2 officers kick, beat w/ club a captured protester. Another approached me: “We love this.” Really. — Christopher Miller (@ChristopherJM) 18 Feb 14

Conscious of the online battle for public opinion, the interior ministry also posted video on YouTube Tuesday that appeared to show that some of the self-defense group members battling the police were also armed.

While the crackdown was initiated by the police — and graphic images of dead protesters were broadcast by at least one Ukrainian channel — officers were also injured and killed in the fighting. One brief video clip uploaded to YouTube on Tuesday afternoon, headlined simply “Captive,” appeared to show an officer with a bloody face who had been captured by protesters.

A crew from Ukraine’s Channel 5, reporting from the near front line on Tuesday afternoon, came across three officers in the hands of the protesters.

Another video clip, posted on YouTube by the Polish journalist Pawel Bobolowicz, showed protesters surrounding a truck and dragging one officer down from the back.