(Corrects day in lead)
* Cultivation school teaches production of high-grade pot
* California, other states have legalized medical marijuana
* Raid dovetails with broad federal crackdown on cultivation
OAKLAND, Calif., April 2 (Reuters) - Federal agents searched a cannabis cultivation college known as the "Princeton of Pot" and briefly detained its founder at his home in a series of raids on Monday in a U.S. government clamp-down on medical marijuana.
The sweep turned Oaksterdam University, which offers courses in the growing and dispensing of marijuana, into the latest flashpoint between federal law enforcement and medical cannabis advocates in California and other states where pot has been decriminalized for medicinal purposes.
"This is clearly an attack on regulation," Oaksterdam University Chancellor Dale Sky Jones said. "They just went after a school that tries to teach people how to do things legally."
Several dozen protesters rallied at the school during the raid, some of them openly smoking joints as they carried signs that read "End federal interference" and "Cannabis is medicine."
Oakland police handcuffed at least one demonstrator, but the reason for the arrest was not immediately clear.
In addition to the college, federal authorities raided the home of veteran medical marijuana activist and Oaksterdam founder Richard Lee, who was briefly detained during the search but not arrested, said Joycelyn Barnes a special agent and spokeswoman for the U.S. Drug Enforcement Administration.
Raids also were conducted at a medical marijuana dispensary run by Lee, a nearby cannabis museum and the home of Todd McCormick, another longtime medical marijuana activist who previously has been arrested for growing pot, Barnes said.
Neither McCormick nor anyone else was arrested in connection with Monday's actions, she said.
Barnes said the raids all were carried out under a federal search warrant that a judge has ordered sealed, and she declined further comment, except to say that DEA officers were joined by the Internal Revenue Service agents and federal marshals.
"This is just part of the three agencies combining resources to investigate criminality involving marijuana," she told Reuters.
Oaksterdam instructor David McCullick expressed outrage at the raids, saying the school was licensed by the city and that its "grow lab" contains fewer than 100 small cannabis plants.
"It's just a school. It's freedom of speech," he said.
MEDICAL MARIJUANA TARGETED
In California and other states that have legalized marijuana for medical reasons, the U.S. government has sought in recent months to shut down storefront medical cannabis shops and greenhouses deemed by federal investigators to be serving as drug-trafficking fronts, as well as those that are located close to schools and parks.
Federal authorities have recently intensified their crackdown in Colorado and Washington state, where voters will be deciding in ballot initiatives in November whether to make those states the first to legalize weed for recreational use.
A total of 16 states and the District of Columbia have enacted some sort of legalized medical-marijuana statutes, according to the National Drug Policy Alliance. But cannabis remains classified as an illegal narcotic under federal law.
The Obama administration has said it would not single out individual patients who possess or grow their own marijuana in states with medical pot statutes. But U.S. Attorney General Eric Holder and various federal prosecutors have said the government would continue to target operations that support for-profit, illegal drug dealing under the guise of medical marijuana.
Oaksterdam, widely referred to as the "Harvard of Hemp" and the "Princeton of Pot," opened in 2007 and bills itself as the first cannabis college in the United States. It holds classes on Wednesday mornings and one weekend every month.
One demonstrator outside the school on Monday, a 50-year-old laborer on disability with a back injury, said he had taken a class called "Horticulture 102."
"I tried it (marijuana) and it worked," said Michael Little Bear. "So the next step was I wanted to make it. There's goodness here. ... They teach the right way to do things," he said. (Additional reporting by Ronnie Cohen; Writing by Steve Gorman; Editing by Cynthia Johnston and Anthony Boadle)