The chair of the Toronto Police Services Board says a request for his resignation over a social media post amounts to a smear campaign.

Alok Mukherjee was asked to resign after he shared an image originally posted by the activist group Occupy Wall St. on his Facebook page.

The photo, which has since been deleted, was comprised of three images with text that said, "Americans killed by ISIS: 3," "Americans killed by Ebola: 2" and "Americans killed by police: 500 + every year."

In a statement released on Friday, the Toronto Police Association said Mukherjee "crossed the line" with the post.

The police union said it showed a lack of objectivity which "indicates he is no longer fit to sit on the police oversight body."

In his response to the statement, Mukherjee said the post was meant to encourage conversation about policing in general, and was not a criticism of the Toronto Police Service.

On Monday, Mukherjee told media that the police union has been calling for his resignation for a long time, and the controversial photo is just another way to get attention for its cause.

CTV Toronto's Ashley Rowe reported that Mukherjee called the move part of a larger smear campaign led by TPA President Mike McCormack.

"There's a culture and there's a history which is not a good one," Mukherjee told Rowe on Monday.

"People who have been vocal about change, about reform -- people who have attempted to bring about changes in the community's interest -- have been hounded and drummed out of office."

Speaking to CP24's Stephen LeDrew on Monday, McCormack called Mukherjee's theory a "lame excuse."

He said the association is not out to get Mukherjee, nor does it target people looking for reform.

"We participate in discussions in the appropriate form. What this is about is nothing more than Mukherjee posting a post which showed a poster from Occupy that said, 'Police are the enemy,'" McCormack said.

"Where's your objectivity? How can you be non-biased from that point forward? That's what this is about, that it showed a lack of judgement."

With a report from CTV Toronto's Ashley Rowe