New York City Mayor Bill de Blasio listens to a question during a news conference in New York January 5, 2015. [Photo/Agencies]

NEW YORK - New York City Mayor Bill de Blasio described a sharp decline in arrests and court summonses in the two weeks since two policemen were shot dead in an ambush as a few "aberrant" days, brushing off reports they were signs of a police work slowdown.

De Blasio, in his first interaction with journalists in two weeks, joined Police Commissioner William Bratton on Monday to announce a continued general decline in serious crime in the city in 2014, which he called a record-breaking year.

"I certainly don't think a few very aberrant days suggest anything compared to what you see over the course of a whole year of success," de Blasio said when asked whether officers were ignoring low-level crimes because of safety fears or in protest against the mayor.

However, both he and Bratton said they needed more time before explicitly ruling out the possibility the sharp decline in police activity was evidence of widespread insubordination.

Tensions have risen between the police unions and de Blasio over his first year in office after the mayor, a liberal Democrat who campaigned on a promise of police reform, expressed qualified sympathy for the nationwide protests that began last summer over police killings.

The rift widened on Dec. 20 when two policemen were shot dead in their parked patrol car by an itinerant, suicidal man who said he was seeking to avenge the deaths of unarmed black men at the hands of white police officers.