Eric Trump has been sent a suspicious package containing white powder, prompting his wife to call the police.

The envelope had a Massachusetts postmark and was addressed to the real estate mogul at his apartment in the Trump Parc East, according to sources as reported by New York Post.

The letter sent a threatening message to Donald Trump’s second eldest son that suggested that he and his siblings would be hurt if their father did not withdraw from the presidential race.

When his wife Lara Yunaska opened the envelope, white powder spilled out.

Police, fire crews and the FBI all reportedly responded to the incident.

It is not clear what the powder was, but initial tests found the substance was not hazardous, as CBS reported.

The incident occurred just one week after Mr Donald Trump’s rally in Chicago was cancelled due to the businessman’s fear that “people would get hurt” amid a spike in aggression and violence against protestors at his gatherings.

Last week a man tried to rush at Mr Trump in Ohio as he passed security staff and climbed onto the stage, prompting Mr Trump to grab the lapels of his nearby security guard’s jacket in surprise.

The hacker group Anonymous warned this week that they would launch a cyber attack on Donald Trump’s various business entities starting on April Fool’s Day.

Mr Trump has angered many people due to his comments about Muslims, Syrians, Mexicans and women.

Marco Rubio, former Republican presidential candidate who dropped out this week, expressed his relief on Tuesday that his team at his former Washington-based headquarters were safe after they were also sent suspicious envelopes containing white powder. The staff had gathered on the roof while authorities investigated.