Gov. Jerry Brown on Thursday vetoed legislation aimed at barring U.S. Immigration and Customs Enforcement agents from arresting undocumented immigrants in state courthouses.

In a brief veto message, Brown said that while he supports the “underlying intent,” he feared what he called “unintended consequences.”

He noted that a bill he signed last year—so-called “sanctuary state” legislation recently upheld by a federal court in Sacramento—calls on the attorney general to draft policies for limiting cooperation with federal immigration officials.

“I believe the prudent path is to allow for that guidance to be released before enacting new laws in this area,” Brown wrote in his signing statement, posted below.

Sen. Ricardo Lara, D-Los Angeles, introduced the anti-arrest legislation in the wake of reports that federal agents were detaining immigrants in state courts as they appeared as litigants, defendants or witnesses.

“When people are afraid to be witnesses or plead their cases it puts the integrity of our courts at risk,” Lara said Thursday in a statement. “I am hopeful that the Department of Justice model policies will help protect the fair administration of justice.”

Chief Justice Tani Cantil-Sakauye decried arrests at courthouses, accusing immigration officials in March 2017 of “stalking undocumented immigrants” and using California trial courts “as bait.” Her remarks drew an angry response from U.S. Attorney General Jeff Sessions and then-Secretary of Homeland Security John Kelly, who criticized the chief justice's use of the word “stalking” and blamed state policies “that occasionally necessitate ICE officers and agents to make arrests in courthouses and other public places.”

ICE officials have said they make arrests in state courthouses because of the set schedule of appearances and because of on-site security screening. Despite the chief justice's pleas, the federal enforcement actions have continued, with ICE agents making high-profile arrests in Sacramento and Fresno courthouses this summer.

Brown on Thursday also vetoed legislation that would have authorized noncitizens to serve on all state boards and commissions. Earlier this year, then-Senate leader Kevin de Leon, D-Los Angeles, appointed Southern California attorney Lizbeth Mateo to a state student grant committee despite her undocumented states.