A 56-year-old man has been arrested in Florida in connection with a mail-bombing campaign aimed at critics of US President Donald Trump.
US officials named the man as Cesar Sayoc. He faces five charges including mailing explosives and threatening ex-presidents.
Mr Trump said the acts were “despicable and have no place in our country”.
Fourteen items have been sent in recent days to figures including ex-President Barack Obama and actor Robert de Niro.
Two were found in Florida and New York City on Friday morning.
Later, two more were discovered in California. Billionaire and Democrat donor Tom Steyer said that a package sent to him had been intercepted at a mail facility in Burlingame, and another addressed to Democrat Senator Kamala Harris was reported in Sacramento.
The incidents come less than two weeks before the US mid-term elections, with politics highly polarised.
Media reports say Mr Sayoc was arrested at a vehicle parts shop in the city of Plantation, Florida.
FBI Director Christopher Wray revealed that he was detained after his fingerprint was allegedly found on one of the packages.
The Department of Justice said the suspect faced up to 48 years in jail.
“We will not tolerate such lawlessness, especially political violence,” US Attorney General Jeff Sessions said at a news conference.
“Let this be a lesson to anyone, regardless of their political beliefs, that we will use the full force of the law against you.”
What do we know about Cesar Sayoc?
Law enforcement agencies said Mr Sayoc lives in Aventura, Florida. He reportedly has ties to New York and is a registered Republican.
In 2002, he was arrested for making a bomb threat in Miami-Dade County, and received one year of probation for the charge.
Mr Sayoc has a criminal record dating back to 1991 in Broward County, according to clerk records. He was arrested, aged 29, on a theft charge. He has also faced charges of fraud and battery.
Court records show Mr Sayoc filed for bankruptcy in 2012 while he was living with his mother. A handwritten note in his bankruptcy report reads: “Lives w/mom. Has no furniture.”