The department assigned the officers to join activists protesting the U.S. war in Iraq and the tactics that police had used at a demonstration a month earlier, a police official said last year in a sworn deposition.

At the first demonstration, police fired nonlethal bullets and bean bags at demonstrators who blocked the Port of Oakland's entrance in a protest against two shipping companies they said were helping the war effort. Dozens of activists and longshoremen on their way to work suffered injuries ranging from welts to broken bones and have won nearly $2 million in legal settlements from the city.

The extent of the officers' involvement in the subsequent march May 12, 2003, led by Direct Action to Stop the War and others, is unclear. But in a deposition related to a lawsuit filed by protesters, Deputy Police Chief Howard Jordan said activists had elected the undercover officers to "plan the route of the march and decide, I guess, where it would end up and some of the places that it would go."

It was revealed later that the California Anti-Terrorism Information Center, which was established by the state attorney general's office to help local police agencies fight terrorism, had posted an alert about the April protest. Oakland police had also monitored online postings by the longshoremen's union regarding its opposition to the war.

The documents showing that police subsequently tried to influence a demonstration were released Thursday by the American Civil Liberties Union, as part of a report criticizing government surveillance of political activists since the terrorist attacks of Sept. 11, 2001. The ACLU said the documents came from the lawsuit over the police use of force.

Jordan, in his deposition in April 2005, said under questioning by plaintiffs' attorney Jim Chanin that undercover Officers Nobuko Biechler and Mark Turpin had been elected to be leaders in the May 12 demonstration an hour after meeting protesters that day.

Asked who had ordered the officers to infiltrate the group, Jordan said, "I don't know if there is one particular person, but I think together we probably all decided it would be a good idea to have some undercover officers there."

Several months after the rally, Jordan told a city police review board examining the April 2003 port clash that "our ability to gather intelligence on these groups and this type of operation needs to be improved," according to a transcript provided by the ACLU.

"I don't mean same-day intelligence," Jordan told the civilian review panel. "I'm talking about long-term intelligence gathering."

He noted that "two of our officers were elected leaders within an hour on May 12." The idea was "to gather the information and maybe even direct them to do something that we want them to do," Jordan said.

"I call that being totalitarian," said Jack Heyman, a longshoremen's union member who took part in the May 12 march. He said he was not certain whether he had any contact with the officers that day.

Jordan declined to comment when reached at his office Thursday. In his deposition, he said the Police Department no longer allows such undercover work.

City Attorney John Russo said he was not familiar with the police infiltration of the protest, but said the city had made "significant changes" in its approach toward demonstrations after the port incident. Police enacted a new crowd-control policy limiting the use of nonlethal force in 2004.

The ACLU said the Oakland case was one of several instances in which police agencies had spied on legitimate political activity since 2001.

Mark Schlosberg, who directs the ACLU's police policy work and wrote the report released Thursday, cited previously reported instances of spying on groups in Santa Cruz and Fresno in addition to the Oakland case. He called on state Attorney General Bill Lockyer and local police to ensure that law-abiding activist groups don't come under government investigation.

"It's very important that there be regulation up front to prevent these kinds of abuses from occurring," Schlosberg said at a news conference.

Schlosberg said the state needs an independent inspector looking into complaints and keeping an eye on intelligence gathering at such agencies as the California National Guard and the state Department of Homeland Security.

Tom Dresslar, a spokesman for Lockyer, said the attorney general had not yet read the ACLU report. But he said his boss "won't abide violations of civil liberties. There's no room in this state or anywhere in this country for monitoring the activity of groups merely because they have a political viewpoint."

Following the Oakland port protest and disclosures about the monitoring of activists, Lockyer issued guidelines in 2003 stating that police must suspect that a crime has been committed before collecting intelligence on activist groups.

But Schlosberg said the ACLU had surveyed 94 law enforcement agencies last year and found that just eight were aware of the guidelines. Only six had written policies restricting surveillance activities, he said.

E-mail Demian Bulwa at dbulwa@sfchronicle.com