US pop star Ariana Grande has paid tribute to Saffie Roussos, the youngest victim of the Manchester Arena bombing.

The eight-year-old was with her family when suicide bomber Salman Abedi detonated a home-made device, killing 22 people including seven children.

Following a concert in Buenos Aires on Wednesday, Grande tweeted: "Saffie, we're (thinking) of you baby" alongside a birthday cake emoji.