Mayor Michael Bloomberg and Police Commissioner Ray Kelly offered robust defense of a secret police department effort to monitor mosques and Muslim businesses and student groups in other states amid criticism from officials who said they were not properly informed of the operation or that the prying went too far.

“Everything the New York City Police Department has done is legal, it is appropriate, it is constitutional," Bloomberg said Friday on his weekly radio show on WOR-AM. "They are permitted to travel beyond the borders of NYC to investigate cases.”

A number of officials and organizations have called for an investigation into the NYPD's monitoring program. However, the New York Attorney General's office on Friday said it could not commence an investigation as a coalition of Muslim and Arab groups had requested.

"While we share some of the serious concerns raised in the letter, there are significant legal and investigative obstacles that impede our ability to launch a review of the matter at this time," a spokesman for the office said.

Kelly said Friday the New York Police Department’s surveillance of Muslims in Newark in 2007 was done in agreement with the Newark Police Department.

“We informed the Newark police officials as to what we were doing.” Kelly said. “We were escorted by Newark police personnel when this survey was being conducted, and we gave them a briefing when it was over.”

Newark Police Director at the time, Garry McCarthy, said he was informed of the operation as a matter of professional courtesy. It remains unclear, however, how many other people were briefed.

According to the Associated Press, New York police officers monitored 44 Muslim mosques, schools and businesses in 2007. Newark Mayor Cory Booker and Governor Chris Christie said they weren't aware of the surveillance.

Kelly said Friday that all operations conducted by the NYPD are “pursuant to the law” and that the department intends to continue doing things it considers necessary to protect New York City.

“We have to be cognizant of what’s going on in the surrounding area, so obviously it would be naïve of us to limit our focus just to five boroughs of New York City,” Kelly said, citing previous terror plots planned outside the city.

He added that, next to following leads, the NYPD is allowed to do “a whole host of things,” such as gather information and develop reports, under the Handschu stipulation.

To settle a federal law suit against the NYPD over its covert surveillance of activists in the 1960s, the police signed off on the so-called Handschu guidelines, named for one of the plaintiffs. The guidelines were designed to protect the Constitutional rights of the general public but were loosened in the aftermath of September 11 attacks.

Meanwhile, Columbia University President Lee Bollinger also spoke out against the NYPD's tactics. The noted First Amendment scholar said the NYPD's monitoring of Muslim students' public websites was an "intrusion" and "raises deeply troubling questions."

He added that police actions could have a "chilling effect" on the free speech and association that the university cherishes.

The AP revealed last week that police monitored Muslim student associations at Columbia, Yale and other colleges in the area.

It's what prompted NYU law student Elizabeth Dann to participate in a roundtable discussion about the police department's actions on Friday at the school's Islamic Center. “If our constitutional rights are of so little interest to the mayor of our own cit,y then I think it makes us all really terrified for what the future is going to hold for our community."

Muddasir Ayaz, a first year medical student, said knowledge of the NYPD’s efforts has altered every day activities at NYU this week. "People are afraid to come to places of prayer, and for Muslims coming to a place of prayer is a really important thing. And associating with other Muslims because there's a lot of fear there will be guilt by association. It also makes it hard for us to connect with people of other faiths because if they operate under the assumption that we’re being watched when they come into contact with us they’ll assume they are too.”

NYU President John Sexton sent a letter to Commissioner Kelly on Friday calling the monitoring of Muslim students on campus “troubling and problematic.”

Muslim students said they’re organizing a "teach in" at NYU next Wednesday in protest.

With reporting by Bob Hennelly, Kathleen Horan and the Associated Press