The incident occurred at about 7:30 p.m. Sunday as the alleged victims exited the public park restroom, police said, adding that the incident was captured on surveillance video and witnessed by several people.
Rene Chalarka, 32, and Dimitry Lugunov, 31, told police they were embracing while they waited to use the restroom at the palm tree-lined Lummus Park when a man called out to them with an offensive word in Spanish for homosexuals, according to a Miami Beach Police Department report.
"We were outside the bathroom and they hit him [Lugunov]," Chalarka, who was visibly injured, told ABC Miami affiliate WPLG-TV.
After hearing the epithet, Chalarka said, he saw a man strike and knock his friend to the ground as "other people came and started hitting.”
"I didn't see anything coming; they were mostly in my face," he added.
A good Samaritan attempted to intervene but, Miami Beach police spokesman Ernesto Rodriguez told WPLG, "he was attacked as well."
The initial suspect, seen in the surveillance footage without a shirt and wearing a dark-colored swimsuit, allegedly "yelled at [Lugunov]," using the slur "before hitting him several times," according to the police report.
Three other men -- one in a blue T-shirt, another wearing a white T-shirt and red shorts, and another wearing a gray T-shirt -- dropped what they were holding and punched the alleged victims, including the good Samaritan, authorities said.
The suspects then "fled south on the beach" as Chalarka recorded the men on his cellphone, according to the police report.
"The four subjects fled the area in a calm way -- they walked away," Rodriguez, the Miami Beach Police spokesman, said.
The alleged victims suffered bruises and cuts, police said.
Police Monday released the surveillance video capturing the incident and additional footage of the four men strolling away and sharing laughs.
Meanwhile, Chalarka said he was a victim of pure hate.
"We were together, so for me, the way we were dressed, it's like, yes, it was a hate crime," Chalarka said. "Why, you know, why us?
"Why these things still happen and here in Miami?"
ABC News' Rachel Katz contributed to this report.