Trump recently endorsed the body-slamming of a reporter, routinely denounces the press as "fake news" and has leveled toxic remarks in the past against the pipe bomb targets.
Authorities have not said whether the van seized in Florida was linked to Sayoc. Sessions made the announcement on Friday in Washington. The 13 bombs found so far were not "hoax devices", he said, calling them "IEDs", or improvised explosive devices.
Investigators have declined to say whether the devices were built to be functional. Wray added that investigators had matched fingerprints and genetic material on the bombs to Sayoc. He was arrested there at an AutoZone auto parts store, where two witnesses told Reuters they heard a loud blast at the time of the arrest.
Mr Sayoc's home address was listed in public records as an upscale gated apartment complex in the seaside town of Aventura, Florida. The van has several stickers on the windows, including American flags, decals with logos and text.
The packages were similar to 10 other crude pipe bombs mailed to prominent Democrats and liberal supporters, and progressively discovered in sorting facilities and mail boxes since Monday. Sayoc lives in Aventura, Florida, and investigators believe numerous packages were processed at a nearby mail facility.
Details suggested a pattern - that the items were packaged in manila envelopes, addressed to prominent Trump critics, carried United States postage stamps and had the same return address for Florida-based Democratic Congresswoman Debbie Wasserman Schultz. None of the devices exploded. He said there was no imminent danger to the Time Warner Center, where CNN's NY office is located. CNN President Jeff Zucker sent a message to staffers saying the package was intercepted at a post office, and he reiterated that "all mail to CNN domestic offices is being screened at off-site facilities".
Who is Cesar Sayoc Jr., the man arrested in plot to mail bombs to Trump critics?
The first bomb discovered was delivered Monday to the suburban NY compound of Soros, a major contributor to Democratic causes. He also has been accused in the past of threatening to use a bomb. In one of his last posts, Mr. Sayoc posted a rant about former Secretary of State Hillary Clinton and former President Obama, both of whom received packages this week.
Federal Bureau of Investigation agents found a "latent fingerprint" on the envelope containing the explosive that he sent to Democratic Rep. Maxine Waters that they identified as Sayoc's. She is a former chair of the Democratic National Committee.
Double Oscar victor and biting Trump critic De Niro on Friday urged people to vote in the November 6 elections, one day after a device was discovered at the Manhattan offices of his production company.
Police found two of the suspicious packages on Friday addressed to US Senator Cory Booker and James Clapper, the former US director of national intelligence, officials said.
"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". Clapper said anyone who has criticized Trump should take extra precautions when handling their mail, adding: "This is not going to silence the administration's critics".
Tensions are running high ahead of the November 6 elections that could shift the balance of power in Congress, which is now controlled by Trump's fellow Republicans.
Son uses blowtorch to kill spiders, sets parents' California home on fire
Firefighters believe the blowtorch ignited some flammable material through a crack in the bricks. This type of spider isn't aggressive and their bites are rare but can be extremely painful.