WASHINGTON — A Florida man with a lengthy criminal history launched a "cowardly and reprehensible" nearly weeklong campaign targeting prominent Democrats and critics of President Donald Trump with more than a dozen potentially deadly improvised explosive devices, federal officials said Friday.

The FBI arrested Cesar Altieri Sayoc, 56, of Aventura, Florida, through a latent fingerprint found on a package sent to California Democratic Rep. Maxine Waters, according to charging documents.

Sayoc has been charged by Manhattan federal prosecutors with interstate transportation and illegal mailing of explosives, threats to former presidents and certain other persons; threatening interstate communications and assault on former and current federal officers. The charges, officials said, could change or expand. Sayoc coiuld face up to 48 years in prison.

FBI Director Chris Wray said Sayoc, a registered Republican, operated on his own, sending mail bombs to former President Barack Obama, former Vice President Joe Biden, former Secretary of State Hillary Clinton and other top Democratic officials, donors and entertainers.

“We do believe that we’ve caught the right guy," Wray said at an afternoon news conference in Washington to unveil the charges. "But we also know that this is an ongoing investigation, and there is a lot of work still to be done, which means there are still many unanswered questions."

Wray said the packages were not "hoax" devices, as some conservative Trump critics have suggested, but that Sayoc's arrest does not mean the danger is over.

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In fact, law enforcement officials Friday said they intercepted a package sent by Sayoc to the office of Sen. Kamala Harris (D-Calif.). Earlier Friday, packages were found in Manhattan and Florida, addressed to Sen. Cory Booker (D-N.J.) and former intelligence director James Clapper, officials said.

“Today’s arrest doesn’t mean we’re all out of the woods,” Wray said. “There may be other packages in transit now and other packages on their way.”

U.S. Attorney General Jeff Sessions and Wray declined to discuss Sayoc’s motivation or why he targeted Democrats.

“He appears to be a partisan,” Sessions said. “That would be determined by the facts as the case goes forward and I’m not going to comment on that.”

Trump Friday evening said he was not responsible for inspiring Sayoc's actions and said he had no intention of toning down his rhetoric or changing his tactics leading up to the Nov. 6 midterm elections.

"I think I've been toned down, if you want to know the truth," Trump told reporters as he left the White House to board Marine One for a political rally in Charlotte, North Carolina. "I could really tone it up because as you know the media's been extremely unfair to me and to the Republican Party."

Trump said he had no intention of contacting the intended bombing victims.

Earlier Friday, Trump praised law enforcement for finding "a needle in a haystack" and said political violence must not take root in America.

“The bottom line is that Americans must unify," he said. "And we must show the world we are united together in peace and love and harmony as fellow American citizens.”

But Gov. Andrew M. Cuomo, speaking to MSNBC Friday, blamed the violence on "overheated, vitriolic rhetoric" from the president.

“This will destroy democracy as we know it if we don’t get it under control,” Cuomo said.

Authorities connected Sayoc to 13 improvised explosive devices made of roughly 6-inch PVC pipe, a small clock, some wiring and “energetic materials” that could heat and explode, Wray said. A DNA sample from two pieces of other IEDs matched the DNA from an earlier arrest in Florida, he said.

The packages were sent to Clinton, Obama, Biden, Harris, Booker, Waters, Clapper, former CIA Director John Brennan through CNN, former Attorney General Eric Holder, billionaire liberal donor George Soros and actor and director Robert De Niro. All are frequent critics of Trump while Biden, Harris and Booker are considered potential Democratic presidential challengers in 2020.

Democratic donor Tom Steyer said Friday that a suspicious package mailed to him was intercepted in California but the incident was not among the 13 cited in the federal complaint.

The packages to Obama, Waters, Brennan and Soros included photos of each of them marked with a red "X," charging papers said. Each package listed the return sender as Rep. Debbie Wasserman Schultz (D-Fla.), whose last name was misspelled, charging documents show. The packages also misspelled the word "Florida," officials said.

None of the devices detonated and no one has been injured.

"This is utterly unacceptable," Sessions said of the IEDs. "Political violence or the threat of violence is antithetical to our vigorous system of self-government."

Geoffrey Berman, U.S. attorney for the Southern District of New York, called the conduct "cowardly and reprehensible and totally anathema to our democracy."

Sayoc will face a judge in Florida Monday, and is expected to be extradited to New York City, where three of the explosive devices were detected.

“Today’s arrest means people are safe,” said NYPD Commissioner James P. O'Neill.

Records show Sayoc, who was born in Brooklyn and lived in Edison, New Jersey, has a long record of arrests in Florida.

In 2002, he was charged with threatening to "throw, place, project or discharge any destructive device." Records show he threatened to throw a bomb at a Florida utility representative and was sentenced to a year of probation.

He also has past arrests for grand theft, petty theft, possession of stolen property, fraudulent refunds, criminal possession of a controlled substance and tampering with physical evidence, records show.

Authorities in Florida Friday seized a white van that prosecutors said belongs to Sayoc. Law enforcement officials told the Miami Herald Friday that Sayoc was living in the vehicle and building the dangerous devices in the vehicle. The van was covered in stickers showing support for Trump and other Republicans and threats to Democrats, with crosshairs over photos of Obama, Clinton and filmmaker Michael Moore.

Social media postings from Sayoc, cited in the charging documents, were highly critical of Soros, who received the first IED, and Florida Democratic gubernatorial candidate Andrew Gillum.

Records show Sayoc, who declared bankruptcy in 2012, listed his employment as a store manager for a small company called Hassanco Investments Inc. in Hollywood, Florida. According to Florida corporate filings, Sayoc registered in 2016 as the manager of Native American Catering and Vending LLC.

In Manhattan Friday, one of the packages went through a mail sorting facility addressed to Clapper at the Time Warner Center. The building is home to CNN, which was evacuated Wednesday after receiving a suspicious package sent to Brennan, the NYPD said.

A postal worker discovered the suspicious package Friday, said John Miller, who oversees the NYPD’s counterterrorism operation.

"One postal worker — who, when she saw this, recognized it — froze it in the system, and was able to resolve that before it got delivered to a location in Manhattan," Miller said.

In a pair of tweets early Friday, Trump criticized the media for its coverage of the packages and complained that the incidents could hurt Republicans running for Congress in the midterm elections just a few days away.

“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!’,” he tweeted shortly after 3 a.m.

He later tweeted: "Republicans are doing so well in early voting, and at the polls, and now this 'Bomb' stuff happens and the momentum greatly slows — news not talking politics. Very unfortunate, what is going on. Republicans, go out and vote!"

With Laura Blasey, Matthew Chayes, Stefanie Dazio, Anthony M. DeStefano, Candice Ferrette, Nicole Fuller and Robert E. Kessler.