A freelance photographer who was struck in the head by a police baton while working on assignment for The Chronicle was among members of the news media who reported being mistreated by police officers in Berkeley during a protest over the weekend.

Sam Wolson, 25, said a Berkeley police officer struck him about 7:30 p.m. Saturday as he crouched to take pictures between a line of officers and protesters outside Berkeley police headquarters on Martin Luther King Jr. Way. The baton strike came after officers had touched Wolson twice, apparently to stop him from moving near the line, he said.

A YouTube video of a CNN news report, posted at http://bit.ly/1w72f5F, shows the officer hitting Wolson with a baton roughly 30 seconds into the segment.

“I was really surprised and disappointed, and a little bit angry,” Wolson, who suffered a mild concussion, said Monday. “People might disagree with how much the media represents the situation, but if you can’t have media safely holding accountable anybody in that situation, then the whole entire system breaks down.”

Wolson said he saw other people “getting treated much worse.”

Chronicle Managing Editor Audrey Cooper said Wolson was “exercising a constitutional right to document the dramatic and tense scene between police and protesters. He was clearly identifiable as a member of the press. The officer had no reason to strike Sam with his baton. We are very concerned about this officer’s actions and plan to deal with city leaders and police officials about this incident.”

In a statement late Monday to “media friends,” Berkeley police said that because of the chaotic protest environment, “it can be difficult for line officers to quickly differentiate demonstrators from media journalists who need access.” Police recommended that journalists cover protests from the side of police lines and not directly in between police and protesters.

Also Saturday night, KTVU TV reported that a news crew was roughed up by police. “We became caught in the current,” reporter Katie Utehs said on that night’s broadcast, as a video showed an officer striking a news photographer with a baton. “Jabbed by a baton, pushed back from the police line, as people hurled rocks at officers.”

The Northern California chapter of the Society of Professional Journalists wrote a letter Sunday to Berkeley Police Chief Michael Meehan and Mayor Tom Bates to protest the treatment of journalists covering the protest and ask for an investigation into “inappropriate uses of force by officers against members of the news media.”

Henry K. Lee is a San Francisco Chronicle staff writer. E-mail: hlee@sfchronicle.com

Twitter: @henryklee