Tonight at 9 p.m. the Occupy Wall Street movement is sponsoring a Solidarity March with the protesters in Oakland, California, from Zuccotti Park down to City Hall. Last night, police in Oakland fired tear gas, rubber bullets, flash-bangs and bean bag projectiles at OccupyOakland protesters at around 7:45 p.m. Despite authorities claiming [pdf] that there were no injuries to protesters, many photos and videos dispute that notion. According to the Guardian, 24-year-old protester Scott Olson is in critical condition with a fractured skull and brain swelling after being hit by a police projectile. Olson is a veteran of the Iraq War.

Below is a graphic video of Olson being carried away from the a chaotic scene last night. Olson is seen around the 0:40 mark.

This video appears to show Oakland PD officers tossing a flash-bang grenade next to Olson's injured body.

In their initial press release [pdf], the Oakland PD denied using non-lethal projectiles and weapons against the protesters, claiming, "the loud noises that were heard originated from M-80 explosives thrown at Police by protesters." A subsequent release [pdf] states

A large number of officers were assaulted, doused with hazardous materials, and hit with large rocks and bottles, which resulted in the declaration o an unlawful assembly and the order to disperse. To assist in the dispersal efforts, officers used less lethal force tactics.

Below is a video of Oakland PD officer saying he was merely following orders when he used non-lethal weapons.

One protester tells the San Jose Mercury News that police fired the tear gas "because of stupid people who were provoking the cops. It's random people who see a big group and are like, 'let's start a riot.' All it takes is one thing and it's like let's gas everyone."