SACRAMENTO, Calif. -- A California state psychiatric hospital housing mostly sexually violent predators has been locked down and visits canceled after a weekend protest over a crackdown on devices, like flash drives, that officials say are often used to smuggle child pornography. The patients at Coalinga State Hospital were protesting new restrictions on electronic devices, Department of State Hospitals spokesman Ralph Montano said Tuesday, but no injuries were reported.

Department officials have cited lawsuit testimony asserting that there is a "porn epidemic" at Coalinga to justify the crackdown.

At least 200 Coalinga patients have been involved with the possession or transmission of child pornography and there are typically two or three new child pornography cases reported each month which require investigation, officials said. Patients also copy and sell or exchange legal movies and music for profit, the department said.

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The facility in Fresno County can hold nearly 1,300 patients, nearly three-quarters of whom are court-designated sexually violent predators. Most of the remaining patients are being treated for mental illness after completing prison sentences.

A notice on the hospital's website said the visitor center was closed Sunday due to the lockdown until further notice. Department spokesman Ken August said Tuesday evening that patients broke six windows, damaged several electronic messaging boards and clogged a few toilets, but flooding and damage were minimal. Some patients engaged in various forms of disruptive behavior on Saturday, he said, including refusing to follow directions, disrupting patient head counts, threats and property damage.

According to its website, Coalinga is a "self-contained psychiatric hospital constructed with a security perimeter" with more than 1,200 beds.

"This facility treats sexually violent predators. These regulations apply to all state hospitals, however only patients at this hospital have responded in this way," he said in an email.

Los Angeles-based attorney Ezra Landes, who has represented Coalinga patients in a class-action lawsuit alleging poor conditions, said he was concerned that the institution's telephones were shut down or confiscated and detainees were unable to consult with their lawyers.

August said attorneys can meet with their clients in person or talk to them by phone again beginning Wednesday.

The department approved an emergency regulation Thursday attempting to block "the possession, viewing, and distribution of illicit materials" by barring patients from possessing digital memory storage devices such as flash drives or thumb drives, hard drives such as those in computers, memory cards, digital media players and digital media burners.

Patients are allowed only commercially produced CDs, DVDs and game players with no access to the internet.

The department said the new rules are intended to add modern devices to restrictions initially imposed in 2009 to block contraband including illegal pornographic materials and internal and outside communications it said create safety and security risks.

Problems have continued despite the earlier regulations, it said, including the distribution of child pornography. The department made 11 child pornography arrests last year and is working with the Fresno County District Attorney's office to investigate and prosecute additional cases.

It said the 2009 rules have been repeatedly upheld by the courts. "The Court stated that even patient plaintiffs admitted there is a 'porn epidemic' at DSHCoalinga," the department said in outlining one legal decision.

Sacramento-based attorney Janice Bellucci, executive director of the nonprofit Alliance for Constitutional Sex Offense Laws, said the new restrictions appear to continue retaliation against Coalinga patients that infringes on their voting rights.

Hospital and Coalinga city officials blame patients for defeating a 1 percentage point local sales tax increase in November. Coalinga city council members last month sued Fresno County and the county registrar of voters contesting the results of the tax vote because the county included "illegal votes" from hospital patients.

Bellucci said Coalinga staff removed voting rights flyers posted on bulletin boards, notices that were created on some of the same devices that are now banned.