SAN FRANCISCO (REUTERS) - Social media posts praising Wisconsin shooter Kyle Rittenhouse were being widely shared on Wednesday (Sept 2), a week after Facebook and Twitter said such content violated policies and would be taken off their platforms.

On the third night of protests in Kenosha, Wisconsin, 17-year-old Rittenhouse shot three protesters, two fatally, with an assault rifle.

He has been charged as an adult with two counts of first-degree homicide for the deaths of Anthony Huber and Joseph Rosenbaum, and one count of attempted homicide.

Rittenhouse's lawyer has said he plans to argue self-defence.

The protests against police brutality and racism in Kenosha were in response to the shooting of Jacob Blake, a 29-year-old Black man, by police on Aug 23.

Facebook designated the killings a mass shooting and pledged to remove content praising the shooter, but as of Wednesday posts calling Rittenhouse a "patriot" were still racking up thousands of shares, according to data from social media monitor CrowdTangle.

One post, on a page called "Confederate," said Rittenhouse was acting in self-defence against an armed "mob" and contrasted media coverage of the shooting with that of a Black man suspected of involvement in a shooting death during protests in Atlanta.

The criminal complaint against Rittenhouse said two of the people shot appeared to be unarmed and one appeared to be holding a handgun.

The post has been shared more than 600 times, per CrowdTangle, which is owned by Facebook.

Facebook said it was removing content supportive of Rittenhouse and said that posts calling him a "patriot"qualified for removal.

On Twitter, which has removed posts praising Rittenhouse for violating its policy against "glorifying violence," hashtags like in support of Rittenhouse remained widespread.

Twitter said it had stopped certain terms from trending and appearing in search suggestions, but declined to disclose a full list, citing the risk of users circumventing those actions.