The House's top security official is taking notice of a series of recent swatting incidents targeting member of Congress, offering new guidance to their families and offices on how to address them, Axios has learned.

Why it matters: Letters like this are rare – several aides and members of Congress told Axios they have never seen a communication from the sergeant at arms to a congressional spouse — reflecting heightened fears around member safety.

• Sources told Axios that the recent swatting incidents have members and their families particularly on edge.

Driving the news: Just in the past week, House Majority Whip Tom Emmer (R-Minn.) and Rep. Shontel Brown (D-Ohio) have said police were sent to their homes in apparent hoaxes.

What they're saying: In a letter addressed to congressional spouses, a copy of which was obtained by Axios, House Sergeant at Arms William McFarland wrote that there has been an "increased number" of swatting incidents at members' personal residences.

• McFarland said his office "will be planning a virtual conference to discuss swatting with congressional staff," and – at upcoming party retreats – he will "personally be on hand" to discuss security matters with spouses.
• The letter, which was also sent to congressional offices, offered tips for preparing for swatting incidents, including creating a plan with U.S. Capitol Police, signing up for the sergeant at arms' residential and cyber security programs and making contact with local law enforcement.

Zoom in: Swatting, McFarland wrote, "typically involves an unknown call placed to 9-1-1 claiming that there is an ongoing emergency, or a violent crime that has occurred."

• "In a swatting call, the caller falsely claims that they are a Member or associated with the Member and provides the Member's home address."
• The goal of such calls, he said, is to "initiate an emergency response, such as a SWAT team responding to the Member residence, creating a tense and volatile situation."

The backdrop: In addition to Emmer and Brown, multiple lawmakers said they were the target of swatting calls over the holidays.

• "[W]hile at dinner with my wife, cowards 'swatted' my home in Naples," Sen. Rick Scott (R-Fla.) said on X. "These criminals wasted the time & resources of our law enforcement in a sick attempt to terrorize my family."
• Reps. Brandon Williams (R-N.Y.) and Marjorie Taylor Greene (R-Ga.) said they were also swatted.

The big picture: The incidents come amid a broader spike in threats towards members of Congress since 2016, as well as lingering security fears from the Jan. 6 attack on the Capitol.

• Recent disruptive demonstrations over the Israel-Hamas war, including an incident in which protesters blockaded members inside the Democratic National Committee, have also prompted concerns.