Two "suspicious packages" were addressed and sent to former U.S. Vice President Joe Biden on Thursday, according to reports.
Another package was also found at the office of actor and Trump critic Robert de Niro in New York early Thursday.
The New York Police Department (NYPD) said on the package was removed, but a heavy police presence was still expected in the area.
The packages containing explosive devices, are among many that have been sent to prominent figures of the Democratic Party, as well as critics of President Donald Trump.
Packages mailed to billionaire philanthropist George Soros, former President Barack Obama, former Secretary of State Hillary Clinton, former Attorney General Eric Holder, congresswoman Maxine Waters and former CIA director John Brennan.
New York Governor Andrew Cuomo on Wednesday told reporters a package was also sent to his office, however, the NYPD later said, it was not a bomb and unrelated to other packages.
The FBI is conducting an investigation into the matter, and has noted all packages have the same return address of Florida congresswoman Debbie Wasserman Schultz.
"This investigation is of the highest priority for the FBI. 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," FBI Director Christopher Wray said in a statement.
The packages have been sent for further analysis to the FBI laboratory in Quantico, Virginia.
A senior FBI official likened the packaged to domestic terrorism.
"The utilization of violence in order to further one's own political agenda is unacceptable," said FBI Special Agent Bryan Paarmann.
