CNN —  

Stung by the level of violence last weekend, Chicago officials pledged Tuesday to deploy more officers in neighborhoods that have seen a surge in shootings.

Police Superintendent Eddie Johnson told reporters an additional 430 officers are being put on street duty, with 200 more to be on patrol over the weekend.

Some officers will have their hours extended or vacations canceled. Others are being reassigned from other duties, officials said.

During the weekend in Chicago, 66 people were shot, 12 of them fatally, between Friday at 6 p.m. and Sunday at 11:59 p.m.

While officials say killings and shootings have declined over at least 15 months, President Donald Trump has criticized the city’s crime rate, sometimes taking to Twitter to blast what he calls the failure to fight gun violence there. Trump has sent federal authorities to the city to help fight crime.

When asked by a reporter whether the National Guard would be helpful, Johnson and Mayor Rahm Emanuel pushed back, saying the Guard is not trained to handle domestic violence and other calls.

The spate of shootings left Chicago officials visibly frustrated during a Monday press conference, in which they said gun offenders needed to be held accountable, and they pressed for more community cooperation to stem the crimes.

In all, over the weekend, there were 33 shooting incidents. Fourteen juveniles were shot, and two 17-year-olds were killed.

Johnson said 46 people were arrested this weekend on gun charges, and 60 guns were seized as a result of ongoing investigations. However, he said there have been no arrests made in connection with any violence from this weekend.

“Somebody knows who did it. They do. They know that,” the police superintendent said. “They hold me accountable. They hold the mayor accountable. They hold the city council accountable. Where’s the accountability?”

“I never hear people saying, ‘These individuals out here in the streets need to stop pulling the trigger.’ I never hear that. They get a pass from everybody.”

He urged people who know something to come forward.

“These shootings are not random, they’re fueled by gang conflicts. We know who they are and we continue to send a message that it’s OK to commit these crimes by not doing anything as a community. We are all supposed to be on the same side. CPD can be better, but this city can be better,” Johnson said.

Officers investigate a shooting in Chicago on Sunday.

Chicago Mayor Rahm Emanuel also called on community members.

“We as a city, in every corner, have an accountability and a responsibility. If you know who did this, be a neighbor, speak up,” Emanuel said.

Experts say crime tends to pick up during the hot summer months, but Emanuel dismissed that.

“You can talk about the weather, but the weather didn’t pull the trigger,” he said. “You can talk about jobs, and they count, but in parts of the city where there aren’t jobs, people did not pull the trigger.

Chicago has struggled with high shooting and murder rates in recent years. Waller said shootings are down 30% from 2017, and murders are down 25%.

June marked 15 straight months of fewer killings and shootings, police said. However, on June 25, at least 21 were shot and two died.

CORRECTION: This story has been updated to correct the ages provided by Chicago police on the juvenile victims of the weekend violence.

CNN’s Marlena Baldacci, Jay Croft, Deanna Hackney, Eric Levenson and Madison Park contributed to this report.