Since the last week of December, 12 New York City police officers have been attacked by men suspected of crimes — an average of about one a week.

The suspects range from predicate felons to small-time drug dealers. Some have fired blindly at police and others have shot with precision, as did David Garvin when he executed two auxiliary officers in Greenwich Village this month.

There appears to be a pattern to the attacks: Many who are suspected of crimes, especially weapons possession, are choosing to fight rather than submit to arrest. Mayor Bloomberg and the police commissioner, Raymond Kelly, pointed to the trend at a press conference at a hospital in the Park Slope section of Brooklyn on Tuesday night.

“At the same time crime continues to plummet, our police officers keep encountering suspects who would rather fight than be taken into custody,” Mr. Kelly said.

Earlier that night, Officer Rory Mangra, 27, was shot in the ankle while arresting Kingsley Newland, 28, on suspicion of smoking marijuana. Mr. Newland, who has a record of drug possession and sale arrests, was hit with a slew of charges, including attempted murder and assault of a police officer.

Two hours later on Tuesday, David Carter, 19, was arrested for firing several rounds at police officers who were breaking up a fight between several women in the Brownsville section of Brooklyn. Carter recently served nearly eight months of a year-long sentence at Rikers Island on a petit larceny and weapons charge. He was also charged with attempted murder and assault of a police officer yesterday.

Both suspects face up to life in prison if they are convicted.

At a press conference in Staten Island, Mr. Bloomberg once again returned to a signature effort of his second term: reducing the number of guns in the hands of criminals.

“I think what is clear is that more and more guns are appearing in the hands of criminals,” he said, later adding: “I think every parent should take a look at their kids and say, ‘My child is going out on the streets. Do I want to do something to get guns off the streets in big cities?'”

Several criminal justice experts interviewed yesterday said that other factors were also fueling the attacks on police officers.

A senior fellow at the Manhattan Institute, John McWhorter, said the Sean Bell shooting had transformed into a folk-tale of police brutality in high-crime neighborhoods. Anti-police sentiments are imprinted in many young criminals, and shooting a police officer is like a badge of honor, he said.

The chairman of the City Council’s Public Safety Committee, Peter Vallone Jr., said the unprovoked attacks on officers were especially worrying. A man struck an officer in the head with a baseball bat in February in order to steal his gun.

“Officers are being attacked solely because they are wearing blue,” he said.

A professor of police science at John Jay College of Criminal Justice, Eugene O’Donnell, a former police officer, said the majority of recent police officer victims were minorities, which discredits arguments that the clashes are racially motivated.

Having the death penalty for the killing of a police officer would serve as a deterrent, he said.

In New York State, convictions for violent felonies and most drug crimes carry mandatory sentences. Illegal gun possession can lead to federal charges.

The executive director of the Correctional Association, Robert Gangi, said, “In some cases, prison conditions will add to the problem. … New York has a very tough sentencing scheme.”

Meanwhile, the citywide murder rate has averaged less than one a day in the city this year. Mr. Kelly said this was a first in his more than 30 years in the department.