Newtown held a moment of silence and flags were flying at half-staff across Connecticut to mark the fourth anniversary of the Sandy Hook Elementary School shooting.

It was Dec. 14, 2012, when 20 children and six educators were killed by a troubled 20-year-old gunman who shot his way into the Connecticut schoolhouse. Adam Lanza fatally shot his mother before driving to the school, and then killed himself after the rampage.

The town typically does not hold an official memorial event on the anniversary, but prayer services were planned for Wednesday and a counseling center is open for extended hours.

First Selectman Pat Llodra asked town employees to refrain from doing any work, including answering phones, between 9:30 a.m. and 9:45 a.m. to mark the time when the shootings took place.

The anniversary has also served as a launching point for the conversation on gun control in the U.S. to resurface.

With the election of NRA-backed Donald Trump as president, gun control advocates are putting more emphasis on a long-term strategy of electing like-minded lawmakers, passing state legislation and fostering a grassroots network that grew out of the Sandy Hook Elementary School shooting.

Activists say they have generated a big enough support base since the massacre to bypass Washington and push for state-level measures such as universal background checks and persuade more restaurant chains to stop allowing patrons to carry guns.

“We’re pivoting to the states and to American businesses and saying, ‘OK, when Congress won’t protect constituents, it’s up to state lawmakers and companies to protect their constituents and customers,'” said Shannon Watts, who founded Moms Demand Action for Gun Sense in America following the Sandy Hook shooting. “It’s a proven, effective strategy and winning strategy. And we’re going to keep at it as long as it takes — to point Congress and the Supreme Court in the direction the nation is headed in.”

Watts’ group counts 3 million people as members, and she said it has benefited from a surge of interest since the election, with standing-room-only events in West Virginia and the Carolinas following Trump’s win. Among its next priorities, the group wants to help pass a requirement for background checks on gun buyers in New Mexico and to defeat an Ohio bill that would allow guns in areas including daycare centers, police stations and colleges.

Reporting done by The Associated Press.