“This is something that we have to double down on,” Mr. de Blasio said at a news conference on Monday, adding that the rise in shootings was fueled by several factors, but mainly the “dislocation that has happened over these last four months with the coronavirus.”

“The fact that the court system is not working, the economy is not working, people have been penned up for months and months, so many issues underlying this challenge,” he said.

But senior police officials have attributed the rise in violence to criminal justice reforms put in place over the last few years by lawmakers and prosecutors. Those changes, which include efforts by the mayor’s office to reduce the population of the Rikers Island jail complex, have put more violent criminals back on the street and erased deterrents and consequences for carrying guns and shooting them, the police have argued.

“When you take basically half the population of Rikers Island and put it onto the street and then wonder what’s going on, it’s dumbfounding to me,” the police commissioner, Dermot F. Shea, said during a radio interview on 1010 WINS on Monday, alluding to the number of inmates released from the city’s jails during the pandemic.