SAN JUAN, Puerto Rico -- Bernard Hopkins angered fans of Felix Trinidad Jr. by again throwing the Puerto Rican flag to the floor Wednesday in San Juan.

The promotional event for their undisputed middleweight championship fight on Sept. 15 in New York ended abruptly in a near-riot as fans rushed the stage and threw bottles and chairs.

Hopkins, the IBF and WBC 160-pound champion, grabbed a miniature Puerto Rican flag from Trinidad in a New York news conference Monday. The crowd there, however, only taunted Hopkins.

An estimated 5,000 people at a basketball stadium Wednesday greeted WBA champion Trinidad, a Puerto Rican hero, by waving hand-held flags and chanting his nickname: "Tito!"

They jeered Hopkins as he began to speak.

"It will be a sad day for Puerto Rico when you see your hero fall," he said.

Trinidad vowed revenge.

"My Puerto Rican flag is the only thing that I don't allow anyone to touch or throw to the floor," Trinidad said. "You will pay a high price for that."

Hopkins then grabbed the microphone from him. Trinidad slammed it down along with a flag he had plucked from the stage.

Dozens of police officers held back bottle-throwing fans, who kicked the podium. Police escorted Hopkins and Trinidad to separate locker rooms. No one was arrested.