Mayor Antonio Villaraigosa cut short a trade mission to Mexico to deal with fallout from the police department's use of batons and more than 200 rounds of rubber bullets to clear out a park where immigration rights activists were rallying.

"I think it is necessary to make sure people know everything is in order and we will conduct a thorough and transparent investigation," the mayor said late Thursday in Mexico. He was expected back in Los Angeles on Friday afternoon.

Criticism of Tuesday's police action at MacArthur Park grew Friday as did potential legal and political consequences from the scenes of rally-goers and journalists being struck by officers.

KTTV television news camerawoman Patti Ballaz filed a lawsuit seeking unspecified damages against the city and police. The claim alleges civil rights violations, said Kathy Pinckert, a spokeswoman for Ballaz's attorneys.

Ballaz has a fractured wrist and injuries to her ankle and was hit in the breast with a police baton, Pinckert said. She was also suffering from insomnia and mental distress, Pinckert said.

State legislators, immigration activists and others gathered Friday at MacArthur Park to denounce police conduct.

"There are no excuses, a simple apology is not going to suffice," said state Assembly Speaker Fabian Nunez. "To say we are outraged is an understatement. We want those responsible in the highest levels of the LAPD to pay consequences."

Nunez said the department's handling of the rally should be considered in determining whether Chief William Bratton should be given another five-year contract.

"I don't think you heard anybody say Chief Bratton is immune to any of this," Nunez said.

Bratton has expressed "grave concern" about police conduct at the rally and promised a full investigation. He has said the use of force began while officers were dealing with 50 to 100 "agitators" and that objects were thrown at officers.

Victor Narro, an attorney with the National Lawyers Guild who helped organize Tuesday's event, said police had promised to keep him abreast of any potential trouble but his liaison, a police captain, was unreachable.

The guild is reviewing videotape and determining whether to sue the Police Department. He noted that in one tape he saw police fire a rubber round at a boy who appeared to be 10 and "toss him aside like a piece of meat."

John Mack, president of the Police Commission, the civilian overseers of the Police Department, told reporters the clash was "a terrible breakdown" and the panel wants to get to the bottom of who was in charge at the time.

"We have a responsibility to protect individuals while they're expressing themselves," Mack said.

The MacArthur Park melee occurred with the mayor away on a city mission to Central America. Villaraigosa was in El Salvador at the time and continued the trip after video and photos of the incident began to show its scope. His staff said he was in constant contact with police and other officials.

"I was very disturbed by what I saw," Villaraigosa told reporters in Mexico City, where he arrived Thursday.

Also on Thursday, the FBI said it will open a preliminary inquiry to determine "whether the civil rights of protesters taking part in the May 1st immigration rally were violated."

Bratton said he hoped a federal review would show the department has nothing to hide while dispelling any claims that police targeted immigrants or immigrant rights activists.