Two people were killed and multiple people, including a child, were injured in a shooting Sunday evening at a Seattle food festival, a block from the city’s iconic Space Needle, fire officials said.

The Seattle Fire Department said it responded to reports of a shooting just after 6 p.m. at the Seattle Center, which was hosting the annual Bite of Seattle, a three-day festival with thousands expected in attendance.

Two people were declared dead at the scene and four others, the youngest of which was 2-years-old, were transported to a hospital, the department said in a statement. One woman declined going to the hospital, fire officials said.

One suspect was taken into custody by Seattle police, Mayor Katie Wilson said in a statement. Wilson had earlier said two people were in custody, but she later updated her statement.

The shooting is one of at least 271 mass shootings in the US this year, according to the Gun Violence Archive, which defines a mass shooting as one in which four or more victims are shot.

Seattle police responded to a shooting Sunday at the Seattle Center, which was hosting a Bite of Seattle food festival.

Jason Redmond/Reuters

Harborview Medical Center said all patients suffered gunshot wounds and one woman is in critical condition. The range of injuries for the four patients involve the arm, leg, abdomen and lower leg, the hospital said.

The Seattle Center describes itself as a civic, arts and family grounds space that attracts over 12 million visitors each year for events across its 74-acre campus, which includes the Space Needle and the city’s largest arena. The Bite of Seattle Festival features hundreds of local vendors and live music performances, drawing 350,000 guests over three days, its website says.

Videos shared on social media showed crowds of people walking through aisles of vendors outside before gunshots prompted people to flee.

It’s unknown what prompted the shooting.

Two witnesses attending the festival told CNN affiliate KOMO they heard “seven to eight shots,” adding people were running “everywhere.” One man said he was near a stage where a band was playing when he heard “at least two dozen shots,” he told KOMO.

Some people appeared to take shelter in the gift shop of the Space Needle at the Seattle Center, video shared with CNN showed.

Police, emergency responders and officers from several agencies, including the FBI, were at the scene afterwards, video showed. A Washington state SWAT team was also on its way to assist at the request of Seattle police, Gov. Bob Ferguson said.

CNN has reached out to Seattle police and city officials, as well as the Seattle Center, the FBI, the Bureau of Alcohol, Tobacco, Firearms and Explosives.

The mayor called the shooting “an act of horrific violence” and said the community “is trying to understand how a gathering built around culture, connection, and joy ended in gunfire.”

“In the days ahead, we will establish what happened and be transparent with the public about what we have learned,” Wilson wrote. “Tonight, our attention belongs to the people whose lives were taken, those fighting to recover, and the families beside them.”

Ferguson said he was receiving briefings on the shooting and urged people to continue avoiding the area.

The Seattle Center Monorail has announced it would be closed the remainder of the day and would resume operations Monday morning. (CNN, excluding headline)

PHOTO: Police respond to a shooting at Seattle Center during the Bite of Seattle food festival in Seattle on Sunday. Lindsey Wasson/AP via CNN.