HONG KONG >> Hollywood director Michael Bay was attacked and slightly injured on the set of the fourth installment of the "Transformers" movie series filming in Hong Kong, police said.

A police spokeswoman said two brothers surnamed Mak who own a shop near the movie set approached Bay and demanded 100,000 Hong Kong dollars ($13,000) on Thursday.

When Bay refused to pay, they assaulted him, she said. The brothers also allegedly assaulted three police officers who were called to the set.

The spokeswoman said Bay suffered a minor injury to his face but declined medical treatment. She spoke on customary condition of anonymity.

Mak Chi-shing, 27, and Mak Chi-hang, 28, were arrested. They appeared in court Friday, each charged with blackmail and assaulting a police officer. No plea was made and they were remanded in custody until next month.

Paramount Pictures gave a somewhat different account of the incident, which it said occurred on the film’s first day of production in Hong Kong after months of filming on U.S. locations.

It said in a statement that a man rushed onto the set wielding an air conditioning unit and swung it at Bay’s head. It said Bay ducked and wrestled the air conditioning unit away from the man.

Police arrested the man and two companions, and no one on the set was injured, Paramount said.

On his own website, Bay said "drugged up" assailants had been belligerent toward the film crew and one rolled metal carts toward actors on the set while trying to "shake us down." His statement said security personnel subdued one man and that four were arrested for assaulting officers who responded.

Non-violent attempts at extortion involving location filming have been an occasional problem in Hollywood over the years, in which residents would intentionally disrupt filming by making noise or other means in an effort to prompt a payoff. In recent years, studios have been more diligent with compensation to residents in neighborhoods where location shooting is occurring.

Bay has directed the three previous "Transformers" films, in addition to such action flicks as "Bad Boys" and "Armageddon."

"Transformers 4: Age of Extinction" is partly set in Hong Kong. It stars Mark Wahlberg and is to be released next June.