Update: This was posted this afternoon by the St. Paul police:

We were just informed that the officer who had a concrete block dropped on his head during I-94 riot has broken vertebrae.

— Saint Paul Police Department (@sppdmn) July 10, 2016

[End update]

Black Lives Matter protesters in St. Paul shut down the I-94 highway for several hours Saturday night. Police arrested 50 people on the highway and reported 5 officers were injured by thrown rocks, fireworks, rebar and even a Molotov cocktail. From the Associated Press:

Police used smoke bombs to clear demonstrators blocking Interstate 94 in St. Paul late Saturday night during a protest sparked by the recent police killings of black men inMinnesota and Louisiana.

The smoke was used after about 200 protesters refused to leave the roadway just after midnight as police in riot gear slowly moved in. The St. Paul Police Department tweeted that arrests were made, but didn’t indicate how many, and said at least five officers were injured by rocks, firecrackers and other debris thrown by protesters.

St. Paul Police live-tweeted many of the event as they happened:

Traffic alert: I-94 East and Westbound in St. Paul is currently closed due to people marching on the roadway.

— Saint Paul Police Department (@sppdmn) July 10, 2016

‘We ain’t scared’ #I94ShutDown pic.twitter.com/PWAo0ZFEM8

— Libertarian Times (@thezenturtle) July 10, 2016

SPPD negotiating with protesters on I-94 to make symbolic arrests. Protesters in process of choosing those who will be arrested. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

The section of #I94ShutDown willing to risk arrest is nearly ALL WHITE and chanting ‘Black Lives Matter’ … pic.twitter.com/Vmk7IgMe1b

— Libertarian Times (@thezenturtle) July 10, 2016

Officers just gave protesters on I94 the 12th order to disperse. Protesters offered an escort off freeway. They are not moving. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

SPPD has given 16 dispersal orders. Protesters still not leaving the freeway, continue to create safety hazard. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

At this point, some of the protesters started throwing rocks, bottles and fireworks at police. The police responded with inert gas:

Protesters throwing objects at officers. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Officer injured by fireworks thrown by protesters. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Cops: this is unlawful assembly. People: you can't stop the revolution #I94Shutdown pic.twitter.com/lpaVdATgDE

— aisha ☭ (@diligenda) July 10, 2016

Protesters on overpasses throwing objects at officers, dumping liquid on officers. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Officer injured after being hit with a glass bottle thrown by protesters. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Image of fireworks being thrown, injuring officer. #I94closed https://t.co/7QCFi64pMO

— Saint Paul Police Department (@sppdmn) July 10, 2016

Standoff continues on I94 #PhilandoCastile #blacklivesmatter @StarTribune pic.twitter.com/WdkgPuycwn

— Glen Stubbe (@gspphoto) July 10, 2016

Mn state patrol arrested #blacklivesmatter protesters one by one then stopped @StarTribune pic.twitter.com/FARpLj3sXt

— Glen Stubbe (@gspphoto) July 10, 2016

Smoke bombs from St. Paul police didn't disperse #blacklivesmatter protesters @StarTribune pic.twitter.com/q3lxgm22A4

— Glen Stubbe (@gspphoto) July 10, 2016

Protesters are chanting “Hands up, don’t shoot.”

https://twitter.com/MWalsh15/status/752017779272933378

Officers using marking rounds on aggressors. Aggressors still throwing rocks and bottles at officers. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

At some point during the standoff, protesters played Prince’s Purple Rain and sang along, but the rock and firework throwing continued:

#BlackLivesMatter protesters respond to flash bangs, rubber bullets, & smoke grenades w/#PurpleRain.#I94ShutDown pic.twitter.com/JX2YV9GQ1N

— Kris Cruz 🔥 (@realKrisCruz) July 10, 2016

Another officer has been injured by aggressors throwing objects. Three injured so far. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Aggressors still throwing fireworks and rocks at officers' heads. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Rebar is again being thrown at officers from a bridge above the freeway. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Someone just threw a glass bottle from the pedestrian bridge. @MyFOX9 pic.twitter.com/2usOXme2h0

— Samuel King (@SamuelKingNews) July 10, 2016

Rocks being thrown at officers from all directions. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Bricks now being thrown at officers, along with more rocks and bottles. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Inert smoke being used again in an attempt to get protesters to leave the freeway. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Most #blacklivesmatter protesters off I94 heading back to governors residence @StarTribune pic.twitter.com/6wufTb1F9R

— Glen Stubbe (@gspphoto) July 10, 2016

An officer has been hit in the head with a rock. Unclear the extent of injuries. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Another officer hit in the head with a large piece of concrete, possibly dropped from bridge. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Molotov cocktail thrown at officers. Unclear if anyone injured. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

An officer was just hit in face with bottle thrown by a protester on St. Paul street. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

At least five SPPD officers were injured by people throwing rocks, bottles, fireworks and bricks. None seriously. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Finally, hours after the protest began, the interstate was reopened:

Interstate I94 in Saint Paul has re-opened to vehicle traffic. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Police released an update on the number of arrests and the number of officers injured Sunday morning:

Officers arrested 50 people for 3rd degree riot last night on I-94. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Officers arrested 52 people for public nuisance and unlawful assembly during an incident at 4 this morning on Grand and Dale. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016

Last night and this morning, 21 officers from multiple agencies were injured on I-94 and other areas of the city. #I94closed

— Saint Paul Police Department (@sppdmn) July 10, 2016