A suspicious package containing white powder was sent to the home of Sen. Rand Paul, R-Ky., his office said Monday.
"I take these threats immensely seriously. As a repeated target of violence, it is reprehensible that Twitter allows C-list celebrities to encourage violence against me and my family," Paul tweeted.
The suspicious package, which was sent to his Kentucky home, contained a white powder, his office told NBC News. The envelope was being examined for harmful substances and investigated by the FBI and Capitol Police.
It was not immediately known whether Paul was in Kentucky when the package arrived.
Pop singer Richard Marx tweeted Sunday that he wanted to thank Rene Boucher, who was arrested and charged with assaulting Paul in 2017 over a dispute about yard waste that he alleged was being dumped in his yard near the property line.