AUSTIN, Texas — Democrat Beto O’Rourke responded to a heckler at a campaign stop with an expletive after the Texas gubernatorial candidate heard a cackled laugh while criticizing the ease with which the Uvalde elementary school gunman legally purchased an AR-15-style rifle.

By Thursday, video of O’Rourke’s exchange at a town hall in rural Mineral Wells had drawn millions of views on social media, becoming the latest instance in which O’Rourke has gotten attention for his calls for stricter gun laws following one of the deadliest classroom shootings in U.S. history.

O’Rourke on Wednesday was railing against how the 18-year-old gunman in Uvalde was able to legally purchase a weapon “originally designed for use on the battlefields” and take it into a classroom of fourth-graders. When a person in the crowd laughed, O’Rourke paused and pointed in their direction.

“It may be funny to you, (obscenity), but it’s not funny to me,” O’Rourke said.

Supporters stood up and cheered. Video shows a small number of people in the crowd were holding signs for Republican Gov. Greg Abbott, O’Rourke’s opponent in November, though it does not show who O’Rourke was specifically addressing.

Chris Evans, a campaign spokesman, said the town hall continued without any further encounters.

Nineteen children and two teachers were killed in the May massacre. O’Rourke, who has called for raising the age to legally purchase AR-style and other such high-powered guns in the U.S. to 21 years old, interrupted a news conference led by Abbott in Uvalde after the shooting and accused the two-term governor of not taking action.

Gun violence has been one of O’Rourke’s most animated issues as a candidate, including during his run for president in 2019, when he said, “Hell yes, we’re gonna take your AR-15” on a debate stage. He has sought to give a more moderated message on firearms during his run for governor in gun-friendly Texas.