Former Vice President Joseph Biden is among the latest intended recipients of a series of “suspicious packages” sent to Democrats in the United States, reports said on Thursday. The external packing is similar to eight parcels reportedly containing explosive devices sent to CNN and to senior Democrats including former President Barack Obama and former Secretary of State Hillary Clinton earlier this week.

Investigators are examining a package addressed to Biden that was found at a Delaware postal facility, NBC reported on Thursday.

Meanwhile, the New York Police Department is also investigating a “suspicious package” sent to a restaurant owned by actor Robert de Niro in Manhattan’s Tribeca neighbourhood on Thursday, NBC’s New York affiliate News4 reported.

An employee at the restaurant suspected similarities between the package received and the parcels sent to others, that had been shown on news channels, and called the police. A bomb disposal squad was deployed at the site and the package was taken away from the building, an unidentified police official told the local news channel. The police department said the building did not need to be evacuated as it was unoccupied at the time.

So far, the possible explosive devices have been sent to people perceived as critics of President Donald Trump. Besides Obama and Clinton, the list of recipients includes former Central Investigation Agency Director John Brennan (care of CNN), former Attorney General Eric Holder, California Democratic Congresswoman Maxine Waters and liberal philanthropist and financier George Soros.

In June, De Niro made a speech at the Tony awards in New York that was critical of the Trump administration. “I’m gonna say one thing – F**k Trump,” De Niro had said in the opening speech that received a standing ovation.

The Federal Bureau of Investigation said its inquiry into the suspicious packages was of the “highest priority” to the agency. “We have committed the full strength of the FBI’s resources and, together with our partners on our Joint Terrorism Task Forces, we will continue to work to identify and arrest whoever is responsible for sending these packages,” said FBI Director Christopher Wray.

The investigating agency urged anyone with information to contact them. “Do not hesitate to call; no piece of information is too small to help us in this investigation,” the FBI said. “Please contact the FBI at 1-800-CALL-FBI or”

United States President Donald Trump on Wednesday said the media should stop its “endless hostility” and “false attacks”, hours after a suspicious package was found at the Time Warner Center in Manhattan, where news network CNN is based.

Vice President Mike Pence condemned the attacks. “These cowardly actions are despicable and have no place in this country,” Pence said. “Grateful for swift response of Secret Service, FBI and local law enforcement. Those responsible will be brought to justice,” Pence tweeted.