Marchers protesting the Wednesday night shooting death of Philando Castile by police caused an hourslong shutdown of part of Interstate 94 west of downtown St. Paul, starting just before nightfall Saturday, with dozens of police officers decked out in riot gear and using smoke bombs to try to disperse the crowd.

Three officers were reportedly injured after being hit by glass bottles or fireworks thrown by protesters, as demonstrators on an overpass threw objects at officers and dumped liquid on them, according to the St. Paul Police Department Twitter feed.

Police confirmed that I-94 was closed from Hwy. 280 to the downtown St. Paul exits. Earlier, officers were diverting all traffic off I-94 at Lexington Avenue as massive logjams began to form.

As many as 300 protesters were blocking both the eastbound and westbound lanes of the major traffic artery connecting Minneapolis and St. Paul near the Lexington exits. Many sat down on the freeway while others stood, the air filled with yelling and chanting. Around 10:45 p.m., the crowd broke out in a chorus of Prince's "Purple Rain," a Minneapolis anthem. Protesters had a small pickup on the highway with sound ­equipment.

Some onlookers were climbing over the freeway fence to join the blockade, with the crowd swelling as people filled the freeway lanes in both directions.

Just before 10 p.m., authorities set off smoke bombs to disperse the crowd. About 100 feet away from the crowd, a dozen police cars with lights flashing were lined up, with officers addressing the marchers over loudspeakers and ordering them to "leave now" or face arrests.

At one point, two dozen officers in riot gear marched on the crowd, a paddy wagon following behind.

No arrests were immediately reported, said St. Paul police spokesman Steve Linders.

By 10 p.m., officers had issued the 16th order to vacate the interstate, and protesters were not budging.

Marchers, some of whom had earlier demonstrated at the governor's residence on Summit Avenue in St. Paul, were beating drums and chanting slogans, including "Black lives matter."

About 9 p.m. on Twitter, Black Lives Matter Minneapolis posted: "We shut down 94 for Philando. We are gonna need bail money. Please make a gift now."

A throng of onlookers gathered on a pedestrian bridge at Grotto Street — the closest venue to the protest — watching the disruption.

Traffic was stacked in a thick logjam as early as 7 p.m. in both directions and soon came to a standstill.

The protest quickly grew into the day's biggest and most disruptive demonstration in the Twin Cities, following a peaceful daylong protest at the governor's residence and a separate rally at Loring Park that spilled into the streets of downtown Minneapolis, where protesters briefly stopped traffic at 9th and Hennepin, blocked an entrance at the Basilica Block Party and marched past Target Center.

Castile, a 32-year-old school cafeteria worker from St. Paul, was fatally shot by a police officer Wednesday night during a traffic stop in Falcon Heights. The aftermath, as he lay dying in the driver's seat, was live-streamed on Facebook by his girlfriend sitting alongside him while her 4-year-old sat in the back seat.

His death, coming one day after the fatal shooting of another black man, Alton Sterling, in Louisiana and one day before a sniper killed five police officers in Dallas, has put Minnesota in the center of national anguish over race and law enforcement.

For updates on this breaking story, go to startribune.com

Staff writer Kim Palmer contributed to this report.

Randy Furst • 612-673-4224

Twitter: @randyfurst