Two British college students won a Halloween costume contest by dressing up as the burning Twin Towers. (SWNS)

Two British teenagers had an unconventional Halloween costume last week: the burning Twin Towers.

Amber Langford and Annie Collinge, 19-year-old students at the University of Chester, dressed up as the Twin Towers for Halloween. The pair donned American flags on their heads and wore tower outfits that featured planes, explosions, smoke and people jumping to their deaths from the upper floors.

Langford and Collinge won the "best dressed" award at Rosie's nightclub in Chester that night, and received about $240 in shopping vouchers.

"Both the University of Chester and Chester Students' Union utterly condemn the appalling photos which have been shared on social media," said the University of Chester and Chester Students' Union in a joint statement. "Both organizations have begun an urgent investigation into the circumstances around which these images have been taken with a view to taking the necessary action."

The teens said in a statement, "We never meant to be offensive, but we apologize if any offense was caused. The idea was to depict a serious, modern-day horror that happened in our lifetime and was not intended as a joke."

"Although their behavior is insensitive, I think it really reflects the important task that we have to educate future generations," said Mary Fetchet, founding director of Voices of September 11th. "Not focusing on the horror of the day, but about the wonderful lives of those victims who died."