Two brothers charged with trying to extort nearly $13,000 from Hollywood director Michael Bay while he was shooting the latest "Transformers" film in Hong Kong have pleaded not guilty, local media reported Tuesday. Bay was attacked by a man wielding an air conditioning unit and demanding HK$100,000 ($12,900) compensation for filming in the city's Quarry Bay district on the first day of location shooting in October. Brothers Mak Chi-shing, 27, and Mak Chi-hang, 28, who operate an air conditioner shop, each pleaded not guilty to charges of blackmail and assaulting a police officer at the district court on Tuesday, the South China Morning Post reported. The court could not immediately be reached for comment. Police had arrested two men surnamed Mak, aged 27 and 28, after the attack on the "Armageddon" director while he was filming "Transformers: Age of Extinction" in the southern Chinese city. Bay had recounted details of the incident at the time in a statement on his website. "Every vendor where we shot got paid a fair price for our inconvenience, but he wanted four times that amount," he said, adding that he told the man and his friends to "forget it". "He didn’t like that answer. So an hour later he came by my crew as we were shooting, carrying a long air conditioner unit. He walked right up to me and tried to smack my face. "But I ducked, threw the air unit on the floor and pushed him away. That’s when the security jumped on him. But it took seven big guys to subdue him. It was like a Zombie in Brad Pitt’s movie 'World War Z' -- he lifted seven guys up and tried to bite them," Bay said. The director faced a second extortion attempt within a week of filming in the city, with police arresting a 35-year-old male on suspicion of intimidating a member of Bay's film crew. The fourth instalment of the Transformers franchise starring Mark Wahlberg and Nicola Peltz is scheduled to hit theatres in June. Hong Kong's striking Victoria Harbour is believed to be among the film's locations, along with the city's dense and bustling streets. The court case is expected to go on for three days.