Update 8.45 a.m.
Police say they arrested more than 100 people and that 27 officers were injured during Saturday's protests.
St. Paul Mayor Chris Coleman and Police Chief Todd Axtell told a press conference Sunday morning that the protest over the death of Philando Castile became "riot," after officers pelted with rocks, bottles and fireworks.
Some 50 people were arrested during the I-94 shutdown, and a further 52 were arrested as the demonstration continued in the streets of St. Paul after they left the interstate, which re-opened at 9 a.m.
The Star Tribune reports that 21 St. Paul police officers and six state troopers were injured by items thrown by protesters, with one suffering a dislocated shoulder and three in total requiring hospital treatment.
Mayor Coleman called the display "shameful" and said it "doesn't honor anyone's memory," including that of St. Paul cafeteria worker Philando Castile, whose death at the hands of police on Thursday prompted the Black Lives Matter-organized protest which started at 7 p.m. outside the Governor's Residence.
The Pioneer Press reports that Axtell denied claims from protesters that they used tear gas – saying they only used smoke bombs with inert gas that had no irritants.
Coleman also denounced the actions of protesters who brought children to the demonstration and used them "as a human shield" as police tried to get them to move, the Pioneer Press' Mara Gottfried reports.
A public protest over the death of Philando Castile closed Interstate 94 in St. Paul until 1 a.m. Sunday, following a standoff between police and demonstrators.
St. Paul Police Department says five of its officers were injured by fireworks, bricks and bottles thrown, and at one point claimed a molotov cocktail had been thrown.
Police meanwhile used smoke bombs, tear gas and pepper spray, with the Star Tribune reporting officers wearing riot gear confronted protesters as they made their way onto I-94 at Lexington Ave., with "dozens" of people said to have been arrested.
Police also used marker rounds during the standoff, it was reported.
Independent media organization Unicorn Riot was live-streaming the protest and showed the moments when police used smoke bombs, flash bangs and pepper spray on protesters, which you can watch below.
Despite the arrests being made, scores stayed behind, blocking the interstate to traffic before finally dispersing around 1 a.m., when they marched to the Governor's Residence, which is where they had started their protest earlier that evening.
The Pioneer Press reports just under 100 protesters left the Governor's mansion around 2 a.m. and marched east on Grand Ave., chanting "We're just taking a walk!" before they were met by police and state troopers at 2:45 a.m., when several more were arrested.
Final arrest numbers from the protest have not yet been made available.
KARE 11's Adrienne Broadus reported that those responsible for throwing projectiles at police during the I-94 standoff may not have been part of the Black Lives Matter movement, which organized the protest.
Something similar happened during the Jamar Clark protests in Minneapolis last December, when the demonstration was joined by a number of "anarchists" who came from outside the Twin Cities and threw molotov cocktails over police walls.
Marching for Philando
Most of those protesting on Saturday night protest were peaceful, although police had warned people before going out onto I-94 that they faced possible arrest.
The demonstration was the latest in response to the death of St. Paul cafeteria supervisor Philando Castile on Thursday. He was shot and killed by a St. Anthony police officer who pulled him over for a traffic stop.
It had started at Gov. Dayton's residence at 7 p.m., hundreds walked through downtown St. Paul and at one point tried to enter the Basilica Block Party, but were thwarted by police.
It was one of many protests taking place nationwide, with CNN reporting similar demonstrations in Washington D.C., Atlanta and Fort Lauderdale, in response to the shooting by police of Castile and Alton Sterling in Baton Rouge, Louisiana.
At a similar protest in Dallas on Thursday night, a lone gunman who wanted to kill "white people, especially white police" opened fire, killing five police officers and injuring many more.