Federal authorities have detained a person in connection with the mail-bomb scare that widened to 12 suspicious packages, a Justice Department official said Friday.
Department spokeswoman Sarah Isgur Flores said authorities planned to announce more information at a press conference.
Earlier Friday, authorities said suspicious packages addressed to New Jersey Sen. Cory Booker and former National Intelligence Director James Clapper — both similar to those containing pipe bombs sent to other prominent critics of President Trump — had been intercepted.
The discoveries — making 12 so far — further spurred a coast-to-coast investigation, as officials scrambled to locate a culprit and possible motive amid questions about whether new packages were being sent or simply surfacing after a period in mail system.
The devices have targeted well-known Democrats including former President Barack Obama, former Vice President Joe Biden, Hillary Clinton and former Attorney General Eric Holder.
The FBI said the package to Mr. Booker was intercepted in Florida. The one discovered at a Manhattan postal facility was addressed to Mr. Clapper at CNN's address. An earlier package had been sent to former Obama CIA Director John Brennan via CNN in New York.
Attorney General Jeff Sessions said Friday the Justice Department was dedicating every available resource to the investigation "and I can tell you this: We will find the person or persons responsible. We will bring them to justice."
Mr. Trump, on the other hand, complained that "this 'bomb' stuff" was taking attention away from the upcoming election and said critics were wrongly blaming him and his heated rhetoric.
Investigators were analyzing the innards of the crude devices to reveal whether they were intended to detonate or simply sow fear just before Election Day.
Law enforcement officials told The Associated Press that the devices, containing timers and batteries, were not rigged to explode upon opening. But they were uncertain whether the devices were poorly designed or never intended to cause physical harm.
Homeland Security Secretary Kirstjen Nielsen, in an interview Thursday with Fox News Channel, acknowledged that some of packages originated in Florida. One official told AP that investigators are homing in on a postal facility in Opa-locka, Florida, where they believe some packages originated.
The package addressed to Booker was found during an oversight search of that facility, according to a law enforcement official.
The officials spoke on condition of anonymity because they were not authorized to discuss the ongoing investigation by name
Most of those targeted were past or present U.S. officials, but one was sent to actor Robert De Niro and billionaire George Soros. The bombs have been sent across the country - from New York, Delaware and Washington, D.C., to Florida and California, where Rep. Maxine Waters was targeted. They bore the return address of Florida Rep. Debbie Wasserman Schultz, the former chairwoman of the Democratic National Committee.
The common thread among the bomb targets was obvious: their critical words for Trump and his frequent, harsher criticism in return.
Trump claimed Friday he was being blamed for the mail bombs, complaining in a tweet sent before dawn: "Funny how lowly rated CNN, and others, can criticize me at will, even blaming me for the current spate of Bombs and ridiculously comparing this to September 11th and the Oklahoma City bombing, yet when I criticize them they go wild and scream, 'it's just not Presidential!'"
The package to Clapper was addressed to him at CNN's Midtown Manhattan address. Clapper, a frequent Trump critic, told CNN that he was not surprised he was targeted and that he considered the actions "definitely domestic terrorism."
Jeff Zucker, the president of CNN Worldwide, said in a note to staff that all mail to CNN domestic offices was being screened at off-site facilities. He said there was no imminent danger to the Time Warner Center, where CNN's New York office is located.
At a press conference Thursday, officials in New York would not discuss possible motives or details on how the packages found their way into the postal system. Nor would they say why the packages hadn't detonated, but they stressed they were still treating them as "live devices."
The devices were packaged in manila envelopes and carried U.S. postage stamps. They were being examined by technicians at the FBI's forensic lab in Quantico, Virginia.
The packages stoked nationwide tensions ahead of the Nov. 6 election to determine control of Congress — a campaign both major political parties have described in near-apocalyptic terms. Politicians from both parties used the threats to decry a toxic political climate and lay blame.
Trump, in a tweet Thursday, blamed the "Mainstream Media" for the anger in society. Brennan responded, tweeting that Trump should "Stop blaming others. Look in the mirror."
The bombs are about 6 inches (15 centimeters) long and packed with powder and broken glass, according to a law enforcement official who viewed X-ray images. The official said the devices were made from PVC pipe and covered with black tape.
The first bomb discovered was delivered Monday to the suburban New York compound of Mr. Soros, a major contributor to Democratic causes. Soros has called Trump's presidency "dangerous."
This story was reported by the Associated Press. Laurie Kellman, Ken Thomas, Jill Colvin and Chad Day in Washington and Jim Mustian, Deepti Hajela and Tom Hays in New York contributed to this report.