Cleveland officials said Thursday they're balancing public safety with protesters' First Amendment rights as small groups of people continue to criticize a decision not to indict police officers in the fatal shooting of 12-year-old Tamir Rice.

"This is what happens in a democracy," said Police Chief Calvin Williams. "People have the right to get out there and express themselves, and it's our job as a department, as a city, to protect them while they're doing that."

Protests over the Tamir Rice decision in Cleveland have been small so far compared to other cities that experienced unrest after police shootings or unpopular verdicts.

The size of crowds has dwindled from more than 100 people Monday after the grand jury's decision to between 45 and 50 on Wednesday, Williams said.

Decisions on arrests will hinge on whether actions jeopardize safety and if protesters ignore police requests to disperse in such situations, Williams said.

Protesters have been allowed to lay down on streets to block them, but weren't allowed for safety reasons to walk onto an expressway that cuts across downtown, said Williams and Cleveland Mayor Frank Jackson.

Rice was shot in November 2014 at a Cleveland recreation center while playing with what turned out to be a pellet gun.

In announcing the grand jury decision, Cuyahoga County Prosecutor Tim McGinty said it was "indisputable" that the boy was drawing the pistol from his waistband when he was gunned down. McGinty said Tamir was trying to either hand the weapon over to police or show them it wasn't real, but the officer who shot him, Timothy Loehmann, and his partner, Frank Garmback, had no way of knowing that.

Tamir was shot by Loehmann within two seconds of the officers' police cruiser skidding to a stop near the boy.

McGinty said police radio personnel contributed to the tragedy by failing to pass along the "all-important fact" that a 911 caller said the gunman was probably a juvenile and the gun probably wasn't real.

Also Thursday, Jackson said a review of any administrative charges against the officers will be done deliberately.

"We will take whatever time is necessary in order to do this fairly, justly, due process at its core, to come to the right decision," Jackson said.