Donald Trump Jr. and his wife Vanessa speak with Jared Kushner during inauguration ceremonies for the swearing in of Donald Trump as the 45th president of the United States on the West front of the U.S. Capitol in Washington, U.S., Jan. 20, 2017. (Xinhua/REUTERS)

NEW YORK, Feb. 12 (Xinhua) -- U.S. President Donald Trump's daughter-in-law was hospitalized Monday after she was exposed to a white powder when she opened an envelope addressed to her husband, Donald Trump Jr., police said.

Vanessa Trump was taken to a local hospital as a precaution after she opened the letter in her New York residence, Sergeant Lee Jones at the Office of the Deputy Commissioner, Public Information, New York Police Department, told Xinhua via phone.

It's unknown what the white substance inside the envelope was, but Jones said it should be nonhazardous and has been taken to a lab for further examination.

Vanessa Trump called 911 after she started coughing and became nauseous upon opening the letter.

Trump Jr. is the oldest of the president's children.