A worker is hospitalized with head injuries after a medieval tower under renovation partially collapsed in the center of Rome near the Colosseum today, the ANSA news agency reported.

In fact, after the initial collapse, a second one followed, with thick dust covering the area. Another worker was trapped in the debris, but according to Italian media, he is conscious.

Two other workers were slightly injured but refused to be taken to the hospital. Authorities blocked traffic in the area to facilitate the rescue operation, which is continuing with the help of firefighters and special vehicles.

Authorities are investigating the causes of the collapse, with the Rome prosecutor’s office having opened an investigation into the incident.