CBS News, New York — The sound of a motorcycle backfiring sparked widespread panic in Times Square late Tuesday after crowds mistook the noise as gunfire. In the wake of recent mass shootings in El Paso and Dayton, chaos quickly ensued as people raced to escape what they thought could be an active shooter carrying out an attack.

Some on social media claimed that some people screamed "shooter," sending more people stampeding in fear. Many people reported hearing the bangs, but didn't react until the crowds started screaming and running. Others didn't know what was going on and simply followed suit, confused and scared.

Witnesses called it a stampede as people ran away from the area down nearby streets into restaurants, stores and even theaters. Several pedestrians were hurt in the panicked rush. NYPD officials told CBS New York some 22 people were injured, four of whom were sent to a nearby hospital.

Gideon Glick, who plays Dill Harris in "To Kill a Mockingbird" on Broadway, tweeted some of the screaming people fleeing the scene stormed the Schubert Theatre. The stampede made its way into the theater, scaring patrons under their seats and disrupting the production as the cast fled the stage. The production did not continue.

Nearby at Junior's Restaurant & Bakery, a tourist hot spot, patrons dove under tables as those escaping Times Square made their panicked way into the restaurant. Some crawled on the ground as they made their way from the street to the door. Inside, patrons were packed together sitting on the floor, shoulder to shoulder amid spilled drinks knocked over in the chaos.

CBS New York said people were literally running out of their shoes, dropping their bags, jumping over counters, even trampling those who couldn't keep up. Lots of children were crying. Abandoned shoes and purses could be seen on and around the outdoor tables at Junior's.

"They jumped out of shoes," a Times Square employee said. "There were shoes everywhere."

Motorcycle backfire or gunshot?

A Twitter user caught the backfire sounds while capturing video of buildings in Times Square. She posted her video opining the noise didn't sound like a motorcycle backfiring.

"It sounded like gunshots, it definitely did," Harlem resident Even Dore told CBS New York. "Two or three thousand people, maybe, just dissipated into thin air," he added.

Times Square always has a noticeable police presence, though  additional NYPD units quickly arrived on the scene due to a flood of 911 calls. The NYPD was quick to point out the situation was safe on Twitter.

New York City mayor Bill de Blasio also took to Twitter to tell New Yorkers the scene was safe and to condemn the culture of fear.