Others posted about violence. A member of the Facebook group wrote on Wednesday, “This will take more than talk to fix.” Below that post, another member responded with emojis about the explosion.
On Thursday morning, Facebook’s Stop the Steal team’s growth spiked even further, according to data from CrowdTangle, a social analytics tool owned by Facebook.
That’s when right-wing figures like Jack Posobiec, a Trump pro-activist, and Amy Kremer, Ms. Kremer’s mother and founder of a group called Women for Trump, started posting about the Facebook group on Twitter. Ali Alexander, a former political agent named Ali Akbar, has also tweeted dozens of times about the Stop the Steal movement to his 140,000 Twitter followers.
Their message, shared thousands of times, is a call to rally people to join the Facebook group Stop the Steal and to act in local rallies against voter fraud.
Mr. Posobiec wrote: “Within the first few hours, more than 100,000 people joined the Women’s Group for America First, Preventing Stealing.” In the comments below his post, many cheered for the Facebook group’s popularity.
The tweets have helped send more people to prevent theft. Interaction with the Facebook team grew to 36 posts per minute on Thursday morning, up from about one post per minute, according to CrowdTangle data.
Mr. Posobiec, Mr. Alexander and Amy Kremer did not immediately respond to requests for comment.
At Facebook, executives were notified by the Facebook operator of the group when they began flagging posts with the potential for violent calls and protests aimed at disrupting the vote. The company also receives calls from journalists about the group and its explosive growth. In the middle of the morning, the executives were discussing whether they should get rid of Stop the Steal, an employee who participated in the discussions was not allowed to speak publicly.