Former US vice president Joe Biden and Hollywood megastar Robert De Niro were the latest targets on Thursday of a spree of suspicious packages and pipe bombs sent to opponents of Donald Trump as the US president lashed out at the media for stirring up “anger”.

Political foes of the Republican commander-in-chief accused him of inciting violence after pipe bombs were sent to Barack Obama, Hillary Clinton, CNN and other figures who are loathed by Trump supporters.

With midterm elections less than two weeks away, the president reacted first by calling for unity, but then reverting to attacking the media, which he stepped up early Thursday.

“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 tweeted. “It has gotten so bad and hateful that it is beyond description. Mainstream Media must clean up its act, FAST!”

The spree began on Monday with a device found at the New York home of billionaire liberal donor George Soros.

The FBI said a total of seven suspicious packages were sent in New York, Washington and Florida, including to Obama's attorney general Eric Holder and two to Maxine Waters, a California lawmaker.

On Thursday, a New York police bomb squad removed a similar looking package sent to De Niro at the TriBeCa Productions company he co-founded, sending it for analysis.

In June, 75-year-old De Niro received a standing ovation at the Tony Awards in New York for using an expletive to condemn Trump. During the 2016 campaign, the actor slammed the Republican as “blatantly stupid.”

'Endless hostility'

US media reported that a suspicious device was also addressed to Obama's former vice president, Joe Biden, often rumored as a potential Democratic presidential candidate for 2020, in Delaware on Thursday.

The packages were sent in manila envelopes with bubble wrap, marked with computer-printed address labels. Each listed Debbie Wasserman Schultz, former chairwoman of the Democratic National Committee, as the sender, including misspellings of her last name, the FBI said.

CNN evacuated its New York bureau after a pipe bomb was found in the mailroom together with an envelope containing white powder.

The packaging was addressed care of CNN to former CIA director John Brennan, who has appeared on the channel as a guest and is perhaps Trump's toughest critic from the national security community.

CNN is known for its often critical coverage of the Trump administration and has constantly provoked the ire of the president.

On Wednesday, Trump condemned the mail-bombs, saying “acts of political violence” have “no place in the United States.” “The media also has a responsibility to set a civil tone and stop the endless hostility and constant negative, and often times false attacks and stories,” he later told a campaign rally in Wisconsin.

Twitter saw #MAGABomber trending as users flooded the platform with accusations that Trump had incited the attempted attacks and highlighted the toxic remarks he has leveled against the pipe bomb targets in the past.

The FBI, US Secret Service and local police have mounted a full-scale criminal investigation, appealing to members of the public to come forward with any information they may have.

'False attacks and stories'

Liberal and left-wing critics accuse Trump's rhetoric-laden “Make America Great Again” presidency of emboldening right-wing extremists. He recently endorsed the body-slamming of a reporter and routinely denounces critical press as “fake news.”

Top Democrat lawmakers Nancy Pelosi and Chuck Schumer on Wednesday accused Trump of condoning “physical violence and dividing Americans.”

“It's a time of deep divisions, and we have to do everything we can to bring our country together,” said Clinton, who has remained an outspoken political force despite her stunning loss to Trump in 2016.

“There is a total and complete lack of understanding at the White House about the seriousness of their continued attacks on the media,” said CNN president Jeff Zucker.

There has been no claim of responsibility and no one was yet known to have been arrested.

The Secret Service said the Clinton and Obama packages were “identified during routine mail screening procedures” and that neither were ever at risk of receiving them.

Republican lawmakers followed the White House in issuing condemnations.

Soros, the target of the first device, has long been a hate figure for right-wing groups and lives in Bedford, New York, not far from the Clintons.

The 88-year-old is one of the world's richest men and supported Clinton in 2016. He has been accused by nationalists of sponsoring protests and seeking to push a liberal, multicultural agenda.