Washington (dpa) - An anonymous letter containing suspicious white powder was sent to the son of US presidential candidate Donald Trump, various media report Friday.
After initial testing the substance does not appear to be dangerous, broadcasters NBC and ABC report citing police and Trump insiders.
According to reports, Eric Trump's wife Lara opened the letter and white powder fell from it. She immediately contacted the authorities.
ABC reported that the letter had a Massachusetts postmark and held a note threatening more serious measures in the future if Donald Trump did not end his presidential bid.
Eric Trump stood on the stage with his father after Trump's primary victory in Florida on Tuesday.
On a number of occasions, presumably politically motivated letters have been sent in the US containing white powder that is feared to be anthrax. Exposure to the nerve agent can lead to organ failure and death.
Republican front-runner Trump has drawn ire from the Democrat opposition and moderates within his own party over the course of a controversial campaign, with many blaming his fiery rhetoric for violent clashes at rallies.