Washington: Federal agents searched a US mail facility near Miami on Thursday night racing to find who sent 10 pipe bombs to prominent Democrats and critics of US President Donald Trump as leads pointed to Florida as the possible origin of the packages.
Investigators are treating the devices as "live" explosives, not a hoax, said James O'Neill, police commissioner of New York City, where two of the parcels have surfaced since the bomb scare began Monday with a device addressed to billionaire Democratic Party donor George Soros.
Authorities discovered suspicious packages sent to former Vice President Joe Biden and actor Robert de Niro on Thursday, a day after several high-profile Democrats and critics of US President Donald Trump were targeted with similar devices.
None of the nine confirmed devices exploded but authorities stepped up their manhunt for the would-be serial bomber, with crucial congressional elections less than two weeks away in what has become a contentious campaign season.
Leading Democrats called the threats a symptom of a coarsening brand of political rhetoric promoted by Trump, who also condemned the acts but blamed the media, his frequent foil, for much of the angry tone of the time.
A suspicious package addressed to Biden was found at a mail facility in New Castle County in Delaware, a federal law enforcement official told Reuters. MSNBC reported a second suspicious package also was discovered.
De Niro, who received a loud ovation when he hurled an obscenity at Trump at the Tony Awards last June, also was targeted, the official said.
At a Wisconsin rally Wednesday night Trump, who has denounced the media as an "enemy of the people," called attention to "how nice I’m behaving tonight” but on Thursday morning he attacked the media.
"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 wrote. "It has gotten so bad and hateful that it is beyond description. Mainstream media must clean up its act, FAST!"
All the people who were targeted are frequently maligned by right-wing critics, including former US President Barack Obama, former Secretary of State and presidential candidate Hillary Clinton and Obama's Attorney General Eric Holder.
Also targeted were former CIA Director John Brennan, prominent Democratic Party donor George Soros and California Representative Maxine Waters, an outspoken critic of Trump. Two packages were sent to Waters, who Trump has called "an extraordinarily low IQ person."
The bomb packages were sent as the nation prepared for November 6 elections that will decide whether Democrats take control of one or both houses of Congress from Republicans and deny Trump the majority his party now holds in both chambers.
There has been no claim of responsibility.
Several politicians, including US Senate Majority Leader Mitch McConnell and New York City Mayor Bill de Blasio, described the package bombs as an act of terrorism.
"Someone is trying to intimidate. Someone is trying to quash voices in this country using violence," De Blasio said. "I am confident that we will find the perpetrator or perpetrators."
The CNN bureau in New York received a package addressed to Brennan, who has appeared as a CNN analyst, leading police to evacuate the Time Warner building in a busy Manhattan neighbourhood near Central Park.
The package sent to CNN, which Trump has frequently derided for its coverage of him, contained an envelope of white powder that experts were analyzing, New York City Police Commissioner James O'Neill said.
Trump told the Wisconsin rally his government would conduct "an aggressive investigation."
"Any acts or threats of political violence are an attack on our democracy itself," Trump said. "We want all sides to come together in peace and harmony."
Last week, Trump, who joined other Republicans in accusing Democrats of encouraging "mob" tactics, heaped praise on a Montana congressional candidate who assaulted a reporter during his successful 2017 campaign.
The first package turned up on Monday and was addressed to Soros, the billionaire financier and advocate of liberal, open-border values who is a frequent target of right-wing conspiracy theories.
The parcel intended for Holder ended up rerouted to the return address printed on all the packages - the Florida office of US Representative Debbie Wasserman Schultz, a former chair of the Democratic National Committee, according to the FBI.
The FBI said on Wednesday the packages consisted of a manila envelope with a bubble-wrap interior containing "potentially destructive devices." Each bore a computer-printed address label and six "Forever" postage stamps, the FBI said.
Other officials said the devices contained in the envelopes were similar to the one found in the mailbox of the Soros home and later detonated by police. At least one bomb was packed with shards of glass, a federal source said.