On Wednesday, the Secret Service intercepted "potential explosive devices" addressed to former President Barack Obama and former presidential candidate Hillary Clinton.
New York police also evacuated the Time Warner Center Wednesday to investigate another suspicious package sent to the CNN news offices there, addressed to John Brennan, a former CIA director and frequent Trump critic.
On Monday, a similar device was discovered at the Westchester County home of billionaire Democratic political donor George Soros.
The office of Democratic Rep. Debbie Wasserman Schultz in Sunshine, Florida was also evacuated Wednesday after a suspicious package was found there.
Rep. Maxine Waters, D-Calif., said her office in Washington was also "the target" of a suspicious package on Wednesday, and the FBI later confirmed that another package had been sent to Waters' district office in California.
No injuries from the explosives have been reported so far, but several have been "proactively detonated" by bomb squads, proving that they were intended to harm, and not merely to frighten, their recipients.
The pipe bombs appear to have targeted top Democrats and other public figures who have been outspoken critics of President Donald Trump.
Several of the targets, like Waters and Brennan, only became widely known to the public after Trump singled them out for attacks on Twitter and at his raucous political rallies.
At a rally on Wednesday night, Trump called for a return to "civility." But by Thursday morning, the president was back to blaming one of his most perennial targets, the news media, for the anger which infuses today's politics.
"A very big part of the Anger we see today in our society is caused by the purposely false and inaccurate reporting of the Mainstream Media that I refer to as Fake News," Trump tweeted. "It has gotten so bad and hateful that it is beyond description."
Brennan, who was targeted with a pipe bomb sent to him at CNN's headquarters, responded forcefully to the president's tweet.
"Stop blaming others. Look in the mirror. Your inflammatory rhetoric, insults, lies, & encouragement of physical violence are disgraceful," Brennan tweeted. "Clean up your act....try to act Presidential. The American people deserve much better. BTW, your critics will not be intimidated into silence."
Read the complete NBC News New York report here.