Activision Blizzard is accused of monitoring its staff and threatening them.

A federal labour agency alleged on Friday that Activision Blizzard had illegally surveilled workers during a walkout and threatened to shut down internal chat channels as a union attempted to organise its staff.

According to a National Labor Relations Board spokeswoman, the organisation will file a complaint against Activision if it doesn’t reach a settlement regarding workers from its subsidiary Blizzard Entertainment who are based in California and three other states.

The Call of Duty creator has been charged with a number of illegal labour practises by the Communication Workers of America union (CWA), which has attempted to organise video game testers and other staff members at the company and its subsidiaries.

The nation-wide walkout by Blizzard employees last year was in protest of what they perceived to be a lack of gender equality at the company.

According to Kayla Blado, a labour board spokeswoman, a regional agency official had agreed with the CWA’s assertion that Activision employed security personnel to monitor employees during the walkout.

The company was also found to have violated the law by threatening to ban internal Slack channels where workers frequently discussed working conditions, Blado said.

In a statement, an Activision representative defended the company’s capacity to stop “toxic workplace behaviour.”

“CWA wants us to accept their… false claims, but we strongly believe employees shouldn’t have to put up with insults and put downs for their hard work – especially on company communication platforms,” the spokesperson said.

A request for comment from the union did not receive a prompt response.

Activision is currently dealing with a separate NLRB complaint that was filed last year and claims the company used a policy limiting what employees can post on social media to prevent them from discussing working conditions. Activision has claimed that its social media policy is legitimate and does not prevent employees from using their legal options under US labour law.

Employees in Boston are pushing for an election, and small groups of employees at Activision subsidiaries in New York and Wisconsin recently voted to join the CWA. In those situations, Activision has stated that it is thinking about its options.

Microsoft, the maker of the Xbox, last year agreed to purchase Activision for $69 billion (roughly Rs. 5,67,000 crore), a transaction that has come under scrutiny from US and European antitrust authorities.