The Swedish Royal Family (L-R) Princess Sofia, Crown Princess Victoria, Prince Daniel, Queen Silvia and King Carl XVI Gustaf arrive at Stockholm City Hall for the official ceremony with a minute of silence at noon to remember the victims of Friday's terror attack on Drottninggatan, Stockholm, April 10, 2017. Four people died and fifteen were injured when a truck plunged into a crowd at a busy pedestrian street in the Swedish capital on April 7, 2017. / AFP PHOTO / TT News Agency / Fredrik SANDBERG / Sweden OUT (Photo credit should read FREDRIK SANDBERG/AFP/Getty Images)

The Swedish Royal Family (L-R) Princess Sofia, Crown Princess Victoria, Prince Daniel, Queen Silvia and King Carl XVI Gustaf arrive at Stockholm City Hall for the official ceremony with a minute of silence at noon to remember the victims of Friday's terror attack on Drottninggatan, Stockholm, April 10, 2017.
Four people died and fifteen were injured when a truck plunged into a crowd at a busy pedestrian street in the Swedish capital on April 7, 2017. / AFP PHOTO / TT News Agency / Fredrik SANDBERG / Sweden OUT        (Photo credit should read FREDRIK SANDBERG/AFP/Getty Images)