A suspect package similar to those sent to senior public figures has been sent to a New York restaurant owned by the actor Robert De Niro, the FBI has said.
The device was found at the Tribeca Grill in Manhattan early on Thursday local time, said the city's mayor.
Former Vice-President Joe Biden has also received two suspect packages.
The latest incident marks the eighth critic of President Donald Trump to receive such a package this week.
The #FBI has confirmed three additional packages, similar in appearance to the others – one in New York addressed to Robert DeNiro, and two in Delaware addressed to former Vice President Joseph Biden.— FBI (@FBI) October 25, 2018
De Niro - the star of films Raging Bull and Meet the Parents - is a vocal Trump opponent.
In the past he has called him "a national disaster", "a mutt who doesn't know what he's talking about" and said that he wanted to "punch him in the face".
When the Oscar-winner attacked him at the Tony Awards in June, the president responded by calling De Niro a "very low IQ individual".
The New York Police Department said the restaurant building - which also houses his production company TriBeCa Films - was empty at the time the suspicious device arrived, NBC reports.
New York City Mayor Bill de Blasio praised the "really quick-witted work of a security guard" who alerted authorities.
According to the Associated Press, the security guard was off work on Thursday and had seen an image in a news report of the packages others had received.
That individual then recalled spotting something similar in the building's mailroom and immediately called authorities who removed the device around 06:30 local time (11:30GMT), AP reports.
"We have to be ready for any eventuality," Mr de Blasio said. "It might be hours, it might be days, it might be weeks."
Shortly after the news about De Niro's restaurant broke, President Trump appeared to pin the blame on the media, tweeting: "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."
He made no direct reference to the device found at the restaurant, or any of the earlier incidents.
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. It has gotten so bad and hateful that it is beyond description. Mainstream Media must clean up its act, FAST!— Donald J. Trump (@realDonaldTrump) October 25, 2018
The series of bomb alerts began on Monday, when explosive devices were sent to locations in New York, the Washington DC area and Florida.
The first was found in the post box of billionaire businessman George Soros, a major Democratic Party donor.
Other devices were sent to the following individuals, according to the FBI:
- Former Secretary of State Hillary Clinton
- Former President Barack Obama
- Former Vice-President Joe Biden
- Former CIA Director John Brennan, care of CNN
- Former Attorney General Eric Holder
- California Democratic Congresswoman Maxine Waters
CNN's New York office was evacuated on Wednesday morning, after the package addressed to Mr Brennan was found in its mailroom.
Two devices were sent to separate offices for Congresswoman Waters.
Two devices addressed to former Vice-president Joe Biden were discovered in his home state of Delaware on Thursday, investigators said.
None of the devices went off. The FBI has launched a manhunt for their sender.
The attempted bombings come just under two weeks before the mid-term elections, with US politics highly polarised.
President Trump first responded on Wednesday by calling for more civility in public life, saying: "Those engaged in the political arena must stop treating political opponents as being morally defective.
"No-one should carelessly compare political opponents to historic villains, which is done often."
The president made no specific reference to the intended recipients of the packages.
He later told the media to end the "constant negative and oftentimes false attacks".
Former CIA Director John Brennan, who was targeted at the CNN office on Wednesday, tweeted to Mr Trump on Thursday: "Stop blaming others. Look in the mirror. Your inflammatory rhetoric, insults, lies, & encouragement of physical violence are disgraceful."
Stop blaming others. Look in the mirror. Your inflammatory rhetoric, insults, lies, & encouragement of physical violence are disgraceful. Clean up your act....try to act Presidential. The American people deserve much better. BTW, your critics will not be intimidated into silence. https://t.co/cS5qNiuU7o— John O. Brennan (@JohnBrennan) October 25, 2018
Why is this so political?
The president's critics have called his remarks hypocritical, as he often uses vicious language against his opponents and the press.
Last week, he said Congresswoman Maxine Waters, Hillary Clinton and former Attorney General Eric Holder - who were all targeted with suspicious packages - "are losing it", and that "they've gone so far left that they can't even believe that they're over there".
During his campaign Mr Trump promised to pay the legal bills of anyone who assaults a protester and vowed to jail his opponent Hillary Clinton after the election.
CNN's President Jeff Zucker on Wednesday condemned the "total and complete lack of understanding at the White House about the seriousness of their continued attacks". He added that Mr Trump "should understand their words matter".
But conservatives say Democrats are to blame for the state of political discourse in the US.
They say Democrats, including those who were targeted in the bomb scare, have encouraged "angry mob" behaviour.
Republican Congressman Steve Scalise, who nearly died after he was shot in 2017 by a deranged supporter of progressive Senator Bernie Sanders during a morning softball practice, wrote in Fox News on Thursday of the "growing list of violent or threatening actions taken against conservatives by Democrats".
"The threats and the violence have not let up and instead of seeing my Democrat colleagues calling for an end, there have been calls for their supporters to keep going, to do even more to threaten Republicans," he wrote.
He cited multiple examples of Republicans being "chased out of restaurants" and of Republican lawmakers who have received death threats against themselves and their families.
White House spokeswoman Sarah Sanders praised Mr Trump's reaction to the bomb scares on Fox News, saying: "The President, I think could not have been more presidential."
She added that "certainly the media has a role to play in this process" adding that "90% of the coverage of this president is negative despite the historic successes".
"That is not helpful to the American discourse," she added.
Some of Mr Trump's supporters have said they believe the packages are part of a Democratic plot to win votes in the mid-terms, but there is no evidence for this.
An FBI-led Joint Terrorism Task Force "will continue to work to identify and arrest whosoever is responsible for sending these packages," the agency's director Christopher Wray said in a statement.