FILE - In this March 23, 2016 file photo, Sharon Fairley, chief administrator of the Independent Police Review Authority (IPRA) for the city of Chicago, speaks at a news conference in Chicago. IPRA says it will says that it will release videos, audio recordings and reports from about 100 Chicago Police officer-involved shootings to the public Friday June 3, 2016. The materials pertain to still-open investigations. (AP Photo/M. Spencer Green File)

CHICAGO - Authorities released hundreds of videos Friday that offer startling glimpses into violent encounters involving Chicago police, including the fatal shooting of a robbery suspect speeding toward them in a van and an incident when an officer slammed his night stick against a man's head at a party.

The more than 300 video clips — along with audio recordings and police reports — are from 101 incidents investigated by the Independent Police Review Authority. The agency examines misconduct cases and any instance — justified or not — of an officer firing a gun in a manner that could injure someone.

The release marks the start of a new city policy to make public all video in police shootings and other incidents within 60 days as part of an effort to restore public trust in its beleaguered police force.

The video was captured by police dashcams and bodycams as well as surveillance cameras and bystanders recording on cellphones. Thirty of the 101 cases involve deaths, said IPRA spokeswoman Mia Sissac.

One of the videos shows an officer slamming a woman face-first into the hood of a car during a party in a West Side neighbourhood in July 2014. The officer, baton in hand, screams at the crowd: "Get out of the street or you're going to jail," and slams the weapon into the side of a man's head so hard his hat flies off. The city paid each of them $50,000 to settle a lawsuit.

Another shows officers firing at a van that barrels in reverse out of an electronics store. The driver, suspected of robbery, was killed.

Other video shows officers struggling to subdue a shirtless, muscled man on a sidewalk even after shooting him twice. The man, accused of attacking bus passengers, was hit with a stun gun once on the scene and three more times while being transported in an ambulance, authorities said.

Releasing records related to open investigations is nearly unprecedented in a city where the police department for decades had a reputation for secrecy. City Hall fought the release of video showing a white officer shooting black teenager Laquan McDonald 16 times in October 2014. A judge had to compel the city to make it public in November, and the images set off protests forcing steps toward more openness and sweeping changes in the police department.

"These past few months, as the city has struggled with so many questions about policing and about police accountability, it has been clear that we all agree that there's a lack of trust and that increased transparency is essential to rebuilding that trust," said Sharon Fairley, head of the Independent Police Review Authority. "Today represents an important first step toward that end."

There was no initial indication that any of the footage was as explosive as the dashcam video showing the death of McDonald. The officer who shot him, Jason Van Dyke, was charged with first-degree murder just hours before the video was released, and a Cook County judge said Thursday he would appoint a special prosecutor to handle the case.

Many of the cases involved in Friday's release do not include video, and much of the video in the files does not show the actual incidents, capturing only the aftermath.

Since the uproar over the McDonald video, the city has released police reports on that case and thousands of emails between Mayor Rahm Emanuel's office, the police department and IPRA.

Emanuel praised Friday's release but said, "We know there is a lot more work to do."

Emanuel announced in May that he is abolishing IPRA and replacing it with a civilian department that he said will have more independence and resources to do its work.

Craig Futterman, a University of Chicago law school professor who played a key role in forcing the city to release the McDonald video, said it's too early to know whether the latest release of material is a sign of progress.

"Decades of secrecy and institutional denial should give us reason for skepticism about this, but I look forward to seeing whether this will really be a significant step in the direction of transparency," Futterman said. "This really has the potential to mark a new day in Chicago."

In some cities, such as Seattle, nearly all police video is posted online almost immediately. But elsewhere around the country, the public often must wait months or years to gain access to the videos. In some places, the video is never released.

The Chicago police union opposed the release, saying in many cases the videos don't tell the full story. Dean Angelo, president of the Fraternal Order of Police, Chicago Lodge #7, said some of the incidents occurred up to five years ago, and in some cases the officers involved still haven't been interviewed by investigators. Some of the videos are only partial clips of what happened, and don't include audio.

"The concern is they're putting this out there, and (the officers') kids and neighbours are going to see it, and we're not getting the entire incident," Angelo said.

News from © The Associated Press, 2016