12/17/2014 06:42 EST | Updated 02/16/2015 05:59 EST

Mark Fenton said Toronto was under 'threat' during G20

The police officer who gave the order to cordon in protesters at the Toronto-hosted G20 four years ago told a disciplinary hearing Wednesday that he had information that things had the potential to turn violent.

Toronto police Supt. Mark Fenton has pleaded not guilty to five charges including discreditable conduct and unlawful arrest, which relate to a pair of two so-called "kettling" incidents during the G20 that saw hundreds of people arrested — many of whom where never charged.

Fenton was in charge of the downtown core area on June 26 and 27, 2010. He testified Wednesday that the violence police confronted was unprecedented.

Fenton said he had intelligence reports that warned that black bloc anarchists would be descending on the city during the international summit.

He said briefings outlined how anarchists dress all in black so they would be hard to pick out of a crowd.

Fenton said he had reliable information that these anarchists planned "to kill police officers... stab police officers  ... and there was a threat that Toronto was going to burn that weekend."

His testimony is expected to go on for several days.

Fenton's lawyer, Peter Brauti, said Wednesday that his client was "relieved" to have the chance to tell his side of the story.