Labour MP Yvette Cooper has said she alerted police after receiving a tweeted death threat against her children and grandchildren.
The former Cabinet minister received the sinister message on Tuesday from an account that accused her of sending pro-EU "propaganda" by email, adding: "Please stop or I will kill your kids and grandkids".
Cooper reposted the threatening tweet to her followers.
It is understood the account was removed after the MP for Normanton, Pontefract and Castleford reported the tweet.
The incident comes amid an increase in security for MPs following the death of Cooper's Labour colleague and fellow West Yorkshire MP Jo Cox.
The MP died after being shot and stabbed in an attack in Birstall near Leeds on Thursday last week.
A man has been remanded in custody after being charged with her murder.