Apple's lead attorney Bruce Sewell on Thursday delivered some harsh words regarding a DOJ court filing in response to the company's refusal to cooperate in an FBI investigation, saying the government letter "reads like an indictment."

Sewell participated in a conference call with reporters just hours after federal prosecutors filed a formal response in the ongoing San Bernardino encryption case, which read like a point-by-point dismantling of Apple's claims. According to Business Insider, Sewell was not pleased.

"In 30 years of practice I don't think I've seen a legal brief that was more intended to smear the other side with false accusations and innuendo, and less intended to focus on the real merits of the case," Sewell said.

He went on to say that the DOJ brief "reads like an indictment" of Apple and its encryption policies. In today's letter, prosecutors suggested Apple built unbreakable security safeguards into iOS 8 and iOS 9 in part to defy government warrants and proper law enforcement requests for data access.

"This should be deeply offensive to everyone that reads it. An unsupported, unsubstantiated effort to vilify Apple rather than confront the issues in the case," Sewell added.

Apple's general counsel also took issue with allusions to a purported working data access relationship with the Chinese government. He called those allegations untrue and baseless.

"We add security features to protect our customers from hackers and criminals. And the FBI should be supporting us in this because it keeps everyone safe. To suggest otherwise is demeaning. It cheapens the debate and it tries to mask the real and serious issues. I can only conclude that the DoJ is so desperate at this point that it has thrown all decorum to the winds," he said.

Apple sparked a contentious debate over personal data privacy and national security last month when it refused to comply with a court order compelling its assistance in the FBI's investigation into last year's San Bernardino shootings. An iPhone 5c used by terror suspect Syed Rizwan Farook was seized as part of the operation, but agents are unable to thwart its iOS 9 passcode lock. The government sought, and won, a federal court order forcing Apple's help in unlocking the device, but the company has declined, saying that doing so would put millions of other iPhones at risk.

Sewell ended the call with a plea to what appears to be DOJ lawyers, asking the opposing legal team to refrain from escalating tensions further.