A Florida man has been charged with sending at least 13 pipe bombs to critics of Donald Trump across the country — including Barack Obama and Hillary Clinton — as officials look to pin down a motive for the mail bomb spree which has taken place less than two weeks before midterm elections.

Cesar Sayoc Jr, 56, faces five federal charges, which could mean up to 48 years in prison for the undetonated bombs, which were made of six-inch portions of PVC piping, clocks, and would-be explosive materials.

According to a criminal complaint, the packages included photographs of his intended targets, each one marked with a red X.

Mr Sayoc was arrested at an auto parts shop in the Florida city of Plantation. What is believed to be Mr Sayoc’s white van, which was covered in political stickers celebrating Republicans and denouncing President Trump's opponents, was parked outside before being covered with a blue tarp and taken away by federal agents.

Mr Sayoc's arrest on Friday morning came even as the crude devices continued to appear across the country. One of those packages was addressed to Senator Cory Booker, a New Jersey Democrat; another was sent to James Clapper, a former director of national intelligence; and a third was intercepted before it reached Senator Kamala Harris, a California Democrat.

A fourth bomb, found on Friday in a mail facility in California, was addressed to Tom Steyer, a prominent Democratic donor.

US Attorney General Jeff Sessions, announcing the charges, said that the the suspect's arrest should serve as a warning that the United States government would not tolerate violence of any kind being brought against individuals for political beliefs.

He said: “This is a law-and-order administration. We will not tolerate such lawlessness, especially not political violence. … Let this be a lesson to anyone, regardless of their political beliefs, that we will bring the full force of law against anyone who uses threats, intimidation, or outright violence to further an agenda”.

When asked why Mr. Sayoc had sent the bombs to Democrats, Mr Sessions said he was not sure, adding that the suspect “appears to be a partisan.” On what appeared to be Mr Sayoc's Facebook account there were photos of a Trump rally that he attended during the 2016 presidential campaign. He was wearing a red “Make America Great Again” hat.

All told, at least 14 suspicious packages were mailed to various Democrats or progressive activists in the past week, although no explosions or injuries were reported.

(Getty Images) (Getty)

Explosive packages sent to prominent Democrats and CNN Show all 11 1 /11 Explosive packages sent to prominent Democrats and CNN Explosive packages sent to prominent Democrats and CNN Barack Obama The Secret Service intercepted a package en route to the Washington D.C. residence of former President Barack Obama on Wednesday 23 October Getty Explosive packages sent to prominent Democrats and CNN Hillary and Bill Clinton A package was delivered to the Chappaqua, New York home of former US President Bill Clinton and former Secretary of State and Democratic presidential candidate Hillary Clinton on Tuesday 23 October Getty Explosive packages sent to prominent Democrats and CNN Joe Biden Two packages adressed to former Vice-president Joe Biden were found at a sorting facility in Delaware on Thursday 25 October AFP/Getty Explosive packages sent to prominent Democrats and CNN George Soros A package was delivered to the New York home of Billionaire investor and funder of the Democrats George Soros on Monday 22 October AFP/Getty Explosive packages sent to prominent Democrats and CNN CNN and John Brennan A package was delivered to former CIA director John Brennan at the CNN offices in New York on Wednesday 23 October Getty Explosive packages sent to prominent Democrats and CNN Debbie Wasserman Schultz A package was delivered to the office of Democratic Congresswoman Debbie Wasserman Schultz on Wednesday 23 October, it was addressed to former attorney general Eric Holder Getty Explosive packages sent to prominent Democrats and CNN Eric Holder The package that was delivered to the office of Democratic Congresswoman Debbie Wasserman Schultz was addressed to former attorney general Eric Holder Getty Explosive packages sent to prominent Democrats and CNN Maxine Waters Two packages were sent to Democratic congresswoman Maxine Waters on Wednesday 23 October, one to LA one to D.C. Getty Explosive packages sent to prominent Democrats and CNN Robert De Niro A package was delivered to actor Robert De Niro in New York on Thursday 25 October AFP/Getty Explosive packages sent to prominent Democrats and CNN Cory Booker A package found in Florida was addressed to Democratic Senator Cory Booker on Friday 26 October Getty Explosive packages sent to prominent Democrats and CNN James Clapper NYPD intercepted a package addressed to former directo of national intelligence James Clapper on on Friday 26 October AFP/Getty

Mr Sayoc has charged with five federal felony charges, including interstate transportation of explosives, illegal mailing of explosives, threats against a former president, and other crimes. The 56-year-old faces as many as 48 years in prison if convicted

Those four packages intercepted on Friday join ten others that were sent to various officials and activists this week, starting with a package delivered to billionaire donor George Soros. That package was followed by bombs sent to former President Barack Obama, former Vice President Joe Biden, former US Secretary of State Clinton, and former US Attorney General Eric Holder. Further packages were sent to former CIA Director John Brennan, actor Robert De Niro and two packages were addressed to Congresswoman Maxine Waters.

Federal officials said they had tracked down Mr Sayoc, who has a lengthy arrest history, after finding one of his fingerprints on a package sent to Ms Waters, a California Democrat. Mr Sayoc’s identify was confirmed, the officials said, after investigators found a match between DNA samples discovered on two of the packages he sent and DNA collected from previous arrests.

A review of what appears to be Mr Sayoc’s social media accounts show that he frequently posted messages attacking Mr Soros and other Democrats.

It was not immediately clear why Mr Sayoc would have been motivated to allegedly send the pipe bombs to the elected officials, if it was intended as a political message, or if he was motivated at all by Mr Trump’s frequent hostile remarks aimed at both his political rivals and the news media.

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The bombs were nevertheless still described by officials as serious attempt to damage.

“We’re still analysing the devices in our laboratory,” FBI Director Christopher Wray said at the Friday press conference. “These are not hoax devices”.

The president, for his part, called for unity following the mailings, and continued to attack the news media for “fake news” reporting that he said fuels the “Anger we see today in our society”. Offices for news network CNN was among the locations where packages were sent, the network has been a frequent target for Mr Trump's ire.

“I am pleased to inform you that law enforcement has apprehended the suspect and taken him into custody. It’s an incredible job by law enforcement. We’ve carried out a far reaching federal, state, and local investigation to find the person or persons responsible for these events,” Mr Trump said on Friday in the White House. “These terrorising acts are despicable and have no place in our country. No place”.

In an earlier Tweet, Mr Trump had suggested that Republicans had been "doing so well" in early voting before the 2018 midterms next month but "now this 'bomb' stuff happens and the momentum greatly slows."

Mr Sayoc is a registered Republican voter, according to public records, and has owned a dry cleaning business and a catering business.