Vanessa Trump, the daughter-in-law of US President Donald Trump, has reportedly been taken to hospital after opening an envelope containing an unknown substance.

Law enforcement officials told NBC News Mrs Trump opened a letter in her Manhattan apartment addressed to her husband, Donald Trump Jr, that contained what is believed to be white powder.

Mrs Trump and two other people at the residence were taken to New York Presbyterian-Weill Cornell Medical Center as a precaution, the New York City Fire Department told NBC.

There are no reported injuries.

More to come.