Good morning. Police used teargas at Occupy Oakland overnight after scuffles broke out between officers and protesters demonstrating against dozens of arrests.

The 1,000 strong march was intended to reclaim the occupations original base at Frank Ogawa plaza, which police cleared in the early hours of Tuesday morning.

At least 85 people were arrested as the camp was cleared.

Sam Jones writes that on Tuesday afternoon, protesters marched through the streets of Oakland towards city hall, vowing to retake the plaza. During the march, a small group scuffled with police not far from the city centre, and several were arrested.

Reuters reported that police dispersed the crowd with teargas and what appeared to be a stun grenade.

At Frank Ogawa Plaza, police ordered protesters to move away and they were largely co-operative.

"I'm here because I'm incredibly sad and incredibly angry," said one protester, Samsarah Morgan. "I'm hoping our city government comes to their senses and stops dealing with us like a fascist state."

Another protester, Jeremy Tully, a 30-year-old internet company worker, accused the authorities of using unnecessary force.

"I left work early today to come and stand up against the kind of repression that happened this morning," he said.

City chiefs said they had told protesters last Thursday to cease camping and cooking at the plaza. More warnings were issued on Friday and Monday.

Oakland's mayor, Jean Quan, said in a statement that the city had maintained daily communication with the protesters and thanked those who "peacefully complied with city officials".

She added: "Over the last week it was apparent that neither the demonstrators nor the city could maintain safe or sanitary conditions, or control the ongoing vandalism."

There appears to be some contradiction as to whether or not flash bang grenades were used by police last night. Mother Jones had two reporters, Gavin Aronsen and James West on the scene, and claim flash bangs were used:

The Occupy Oakland protests turned violent Tuesday evening when police officers cracked down with rubber bullets* [*OPD denies, but says it cannot speak for 15 other law enforcement agencies on scene], tear gas, and flash-bang grenades on protesters marching through downtown Oakland.

However Oakland police have specifically denied using flash bangs. California's KGO Newstalk radio station has a transcription from a police press conference held this morning. The police spokesman was asked: "Did the Police deploy rubber bullets, flash-bang grenades?"

The answer:

No, the loud noises that were heard originated from M-80 explosivesthrown atPolice by protesters. In addition, Police firedapproximately four bean bagroundsat protesters to stop them from throwing dangerous objects at the officers.

Fox News' reporting on Occupy Wall Street has been criticised by some protesters (there's even a spoof Fox News reporter, complete with cardboard camera and mic, at Zuccotti Park), but undeterred, their reporters continue to plug away – apparently now working on a story which claims homeless people are being "recruited from shelters" to be at Occupy Wall Street. Fox also appears to be pursuing a line which says are being paid "$100 a day".

A Fox News reporter has emailed a list of questions to Occupy Wall Street protesters to try and get a response to the accusations. One protester has kindly shared the email with me – here it is:

1. What role is New York Communities for Change (NYCC) playing in Occupy Wall Street (OWS)? 2. What is your understanding of the participation of Jon Kest, a former ACORN director, in OWS? 3. What is your understanding of the participation in OWS of NYCC Deputy Director Gregory Basta, Jonathan Westin, Allan Harris, and Amelia Adams. 4. How many former ACORN activists from around the country are involved in OWS? 5. Please share your take on accusations that some of the protestors are actually receiving payments, in part funded by NYCC? "Sources" saying that in some cases people are getting $100 a day and that even local NYC homeless people have been recruited from shelters. 6. There are accusations that these hired activists are being used as door-to-door canvassers to collect money that is used to support the OWS protests. 7. How about accusations that cash donations for UFT's PCB campaign is being used on OWS?

I won't name the reporter, but the email was sent to Occupy Wall Street from a Fox News email address.

The protester who shared the email with me said: "It's all baseless stuff we've never heard of before." Interesting...

Just like that, here's the Fox story. It alleges the former activist group ACORN is paying people to attend protests at Occupy Wall Street.

"Dozens of New York homeless people recruited from shelters are also being paid to support the protests, at the rate of $10 an hour, the sources said," the story says.

Here's a longer chunk:

The former New York office for ACORN, the disbanded community activist group, is playing a key role in the self-proclaimed "leaderless" Occupy Wall Street movement, organizing "guerrilla" protest events and hiring door-to-door canvassers to collect money under the banner of various causes while spending it on protest-related activities, sources tell FoxNews.com. The former director of New York ACORN, Jon Kest, and his top aides are now busy working at protest events for New York Communities for Change (NYCC). That organization was created in late 2009 when some ACORN offices disbanded and reorganized under new names after undercover video exposes prompted Congress to cut off federal funds. NYCC's connection to ACORN isn't a tenuous one: It works from the former ACORN offices in Brooklyn, uses old ACORN office stationery, employs much of the old ACORN staff and, according to several sources, engages in some of the old organization's controversial techniques to raise money, interest and awareness for the protests. Sources said NYCC has hired about 100 former ACORN-affiliated staff members from other cities – paying some of them $100 a day - to attend and support Occupy Wall Street. Dozens of New York homeless people recruited from shelters are also being paid to support the protests, at the rate of $10 an hour, the sources said.

This video purports to show Oakland police using a flash bang grenade during the protests.

Police have said they did not use flash bang grenades to clear demonstrators, but some sort of explosive is clearly thrown into the crowd in the footage.

Here's a police demonstration of a flash bang grenade exploding:

Compare that with the device which explodes at the 52 second mark in the previous video. Sound familiar? Hat-tip to my colleague Paul Harris for the link.

This video shows a little more of the lead up from before a police officer throws an explosive device.

From around 30 seconds in, a figure lies prone on the floor infront of the police line, and it looks as if a crowd gathers in a bid to help them. It is then that the explosive device is thrown into the group by police.

The video then cuts to footage of the injured person being carried away, bleeding from a head wound.

YouTube user PlanetEarthAwakens1 identifies the figure on the floor as Scott Olsen, a Veterans for Peace member.

Indybay.org has pictures apparently of Scott Olsen, showing him lying on the floor and then being escorted away.

Jay Finneburg posted the pictures to Indybay. He wrote:

This poor guy was right behind me when he was hit in the head with a police projectile. He went down hard and did not get up. The bright light in the second shot is from a flash-bang grenade that went off a few feet from us. He was eventually taken to highland hospital.

Further down the thread Aaron Hinde writes that the bleeding man is "a veteran and a member of iraq veterans against the war". Hinde adds that he is "in the hospital and stable but he has serious injuries, we will see how he is doing in the morning when he wakes up".

Later a Indybay user named Adele wrote: "I'm at highland [a hospital in Oakland] with Scott now. If ppl saw him get hit, know who brought him in to the hospital or know how to get in touch w his roommate or family, pls msg me. I can't confirm this at the moment."

I can't confirm these accounts at the moment, but am trying to get in touch with all three people who posted regarding Olsen.

Scott Olsen, the protester shown with head injuries, apparently after being hit in the head by a police projectile, has a skull fracture and is in a "serious, but stable condition", according to a fellow protester with him in hospital.

Adele Carpenter, who has known Olsen since July, said she was told by a doctor at Highland hospital, in Oakland, that Olsen "has a skull fracture".

Carpenter arrived at Highland hospital in Oakland at 11pm last night, and has been allowed to visit Olsen – a former US marine, who did two tours of Iraq – this morning, she said.

"I'm just absolutely devastated that someone who did two tours of Iraq and came home safely is now lying in a US hospital because of the domestic police force," Carpenter said.

She said Olsen moved to the Bay area in July. The former marine, 24, left the military in 2010. Olsen is originally from Wisconsin, Carpenter said, adding that his family have been informed about his condition. A "military buddy" is also on his way to visit Olsen in hospital.

Video footage shows Olsen lying prone on the ground in front of police lines. A crowd gathers in an apparent bid to help him, but then scatters when a police officer throws an explosive device into their midst.

I've just spoken to Keith Shannon, roommate of Scott Olsen, the Iraq veteran who is in hospital after apparently having been hit in the head by a police projectile.

Shannon said doctors told him Olsen has a "skull fracture and swelling of the brain". A neurosurgeon will assess Olsen later today to determine whether he needs surgery, Shannon said.

Olsen, 24, was in 3rd Battalion, 4th Marines, before leaving the military last year. He had been opposed to the Iraq war even before his first tour to the country, Shannon said. Shannon and Olsen met in November or December 2005, and share an apartment in Daly City, south of San Francisco.

"It's really hard," Shannon said. "I really wish I had gone out with him instead of staying home last night."

Shannon, who is also 24, said he had seen the video footage showing Olsen lying on the floor as a police officer throws an explosive device near him.

"It's terrible to go over to Iraq twice and come back injured, and then get injured by the police that are supposed to be protecting us," he said.

Shannon said Olsen was hit in the head by a tear gas canister or smoke canister shot by a police officer. He said Olsen had a curved scar on his forehead consistent with a canister

Protesters who had accompanied Olsen to Highland hospital got in touch with Shannon through Facebook, after Olsen said he lived with someone called "Keith". Shannon said he was told Olsen was unable to say his surname.

Olsen's parents, who live in Wisnconsin, have been told he is in hospital and were "probably going to fly out", Shannon said.

Both Olsen and Shannon are members of Iraq Veterans Against the War and Veterans for Peace, Shannon said. He added that Olsen had been opposed to the war in Iraq before his tours of duty. Olsen served in Iraq in 2006 and 2007.

Scott Olsen is in a "critical condition", in Highland hospital, a spokesman for the hospital has just confirmed to me.

(We already knew he was there from the accounts below, but this is the first official confirmation).

Veterans for Peace have released a statement on Scott Olsen, the former marine who suffered a fractured skull in Oakland yesterday.

Veteran For Peace member, Scott Olsen, a Marine Corps veteran twice deployed to Iraq, is in hospital now in stable but serious condition with a fractured skull, struck by a police projectile fired into a crowd in downtown Oakland, California in the early morning hours of today. Other people were injured in the assault and many were arrested after Oakland police in riot gear were ordered to evict people encamped in the ongoing "Occupy Oakland" movement. Olsen is also a member of Iraq Veterans Against the War.

My colleague Paul Harris writes that "the Oakland police department (OPD) has long been one of the most controversial urban law enforcement agencies in America" – with a string of high-profile criminal and brutality allegations going back decades.

It is also tough turf to police. Oakland is a city that has suffered from considerable urban blight, gang problems and drug issues. It is a historic centre of black American culture and radical black politics, having given birth to the Black Panther movement in the 1960s. There have been persistent reports of police criminality and abuse, especially aimed at the city's black population, where community activists say low-level police harassment is a fact of life. Latest census figures show black people make up the biggest single ethnic group in Oakland at 27.3%, with white people at 25.9% and Hispanics at 25.4%. Despite having almost the same size populations in the city, however, white people account for only 16% of OPD vehicle stops, and 6.7% of motorists searched. Black people in Oakland, by contrast, account for a whopping 48% of vehicle stops, and 65.8% of motorists searched. But it is the major incidents that really stand out when examining how OPD polices its community, and in particular the poorer black neighbourhoods of Oakland. In 1968 OPD officers shot and killed Bobby Hutton. The 17-year-old Black Panther party member was involved in a shootout with police, but surrendered and stripped down to his underwear to show he was unarmed. However, he died after being shot by police at least 12 times.

Read Paul's full piece here.