Bulldozers and rescue workers searched through rubble Saturday for two teenage girls feared buried in the collapse of a 900-year-old tower.

Two people were killed and 15 injured when the 255-foot tower crumbled onto a square in this northern Italian town Friday morning.The search for the two girls began after they were reported missing by their parents. They had failed to show up for work or return home Friday.

Throughout the night, bulldozers, firefighters and volunteer rescue workers dug through the tons of bricks and dirt. Authorities said the clean-up operation would last through the weekend.