New York Mayor Michael Bloomberg on Friday defended police surveillance of Muslims who travel between the Big Apple and nearby New Jersey, whose governor has lambasted the controversial scheme.

"A lot of the World Trade Center terrorists that took 3,000 people went back and forth to New Jersey," said Bloomberg, referring to the September 11 attacks in New York more than 10 years ago.

"To say that the NYPD (New York Police Department) should stop at the border is a bit ridiculous."

The NYPD has reportedly monitored Muslims at mosques and universities in New York city, Pennsylvania, New Jersey, New York state, and Connecticut in recent years. Civil rights groups have denounced the measures.

Bloomberg said there is an agreement with New Jersey aimed at combating terrorism, but admitted that he had not recently spoken to state's governor, Chris Christie, or Newark Mayor Cory Booker about the matter.

"What we've been doing in New Jersey is what anybody in this country or in the world can do," said Bloomberg. "You can go to open meetings, and you can go on open websites and look and see what's there."

Governor Christie on Thursday complained that the NYPD was operating beyond its border and questioned if the force thought its "jurisdiction is the world," and questioned if such a policy was "born out of arrogance or paranoia."

Christie said his concern was whether criminal agencies "are not sharing information again," about possible terror attacks in the United States.

"9/11 was not prevented because law enforcement agencies weren't talking to each other, they were being selfish, they were being provincial, they were being paranoid, they were being arrogant," Christie said.

"I do not want to return to those days," he added.