Michael Bloomberg, New York City's mayor, is facing off with Yale University over efforts by the NYPD to monitor Muslim student groups. He won't find an ally among New Jersey universities, either.

The Associated Press revealed Saturday that NYPD officers had kept close watch on websites and blogs maintained by Muslim student associations across the northeast U.S., and in one case sent an undercover officer on a rafting trip with students from the City College of New York.

Yale President Richard Levin said in a statement Monday that monitoring of students based on religion was "antithetical" to the schools' values.

New York Mayor Michael Bloomberg defended the practice. He says there is nothing wrong with officers keeping an eye on websites that are available to the general public.

He said, "I don't know why keeping the country safe is antithetical to the values of Yale."

In New Jersey, Muslim student associations at several universities have signed a letter asking New York's attorney general to investigate reports of secret surveillance.

A Feb. 20 letter from the president of the Association of Muslim American Lawyers cites a series of stories by the AP detailing the monitoring or recommended surveillance of Muslims by the NYPD.

Documents obtained by The Associated Press reveal how the NYPD's intelligence division focused far beyond New York City as part of a surveillance program targeting Muslims.

Police trawled daily through student websites run by Muslim student groups at Yale, the University of Pennsylvania, Rutgers and 13 other colleges in the Northeast. They talked with local authorities about professors in Buffalo and even sent an undercover agent on a whitewater rafting trip, where he recorded students' names and noted in police intelligence files how many times they prayed.

Asked about the monitoring, police spokesman Paul Browne provided a list of 12 people arrested or convicted on terrorism charges in the United States and abroad who had once been members of Muslim student associations, which the NYPD referred to as MSAs. They included Jesse Morton, who this month pleaded guilty to posting online threats against the creators of the animated TV show "South Park." He had once tried to recruit followers at Stony Brook University on Long Island, Browne said.

"As a result, the NYPD deemed it prudent to get a better handle on what was occurring at MSAs," Browne said in an email. He said police monitored student websites and collected publicly available information in 2006 and 2007.But documents show other surveillance efforts continued for years afterward.

In recent months, the AP has revealed secret programs the NYPD built with help from the CIA to monitor Muslims at the places where they eat, shop and worship. The AP also published details about how police placed undercover officers at Muslim student associations in colleges within the city limits; this revelation has outraged faculty and student groups.

Though the NYPD says it follows the same rules as the FBI, some of the NYPD's activities go beyond what the FBI is allowed to do.

Kelly and New York City Mayor Michael Bloomberg repeatedly have said that the police only follow legitimate leads about suspected criminal activity.

But the latest documents mention no wrongdoing by any students.

In one report, an undercover officer describes accompanying 18 Muslim students from the City College of New York on a whitewater rafting trip in upstate New York on April 21, 2008. The officer noted the names of attendees who were officers of the Muslim Student Association.

"In addition to the regularly scheduled events (Rafting), the group prayed at least four times a day, and much of the conversation was spent discussing Islam and was religious in nature," the report says.

Praying five times a day is one of the core traditions of Islam.