The White House welcomed flocks of costumed children to its annual Halloween event where President Barack Obama and his wife, Michelle, gave out candy and fruit bars.

A toddler dressed as the pope who was being pushed in a "popemobile" caught Obama's attention as he and the first lady walked the South Lawn, baskets of goodies in hand for costumed trick-or-treaters.

US President Barack Obama receives a child dressed as Pope Francis on the South Lawn of the White House during a Halloween trick-or-treating celebration in Washington October 30, 2015. Photo: Reuters

The White House facade was partially colored in black and thronged on either side by sinister figures on stilts and plenty of pumpkins, in an effort to turn the grounds into an "enchanted forest."

Meanwhile acrobats, trapeze artists and jugglers entertained the day's guests, local school children and military children, who were dressed as firefighters, princesses and various other characters.

Top prize goes to Lil' Pope. #HappyHalloween https://t.co/WJo1nYUWup

— The White House (@WhiteHouse) October 30, 2015

The first couple did not dress in costume, with Obama wearing a brown cardigan over a gray collared shirt, and Michelle in a multi-colored tee with black jacket.

More than 4,200 people were expected at the event, where White House M&M candies, cookies, kettle corn, fruit bars and baseball cards featuring the first dogs, Sunny and Bo, were distributed.

Halloween decorations are placed at the South Portico of the White House in Washington, DC before President Barack Obama and the First Lady will welcome local children and children of military families to trick-or-treat at the on October 31, 2014. Photo: AFP

The evening also featured the White House's first ever pavilion with La Catrina, the famous skull from Mexican folklore, which is associated with Dia De Los Muertos.