Indonesian rescuers are searching on Sunday for missing students after a prayer hall at an Islamic boarding school collapsed almost a week ago. They have recovered 23 bodies over the weekend search, bringing the death toll to 37, Associated Press reported.

Using jackhammers, circular saws and sometimes their bare hands, rescue teams diligently removed rubble in an attempt to find the 26 missing students. 

The structure fell on top of hundreds ofstudents, mostly boys between the ages of 12 and 19, on Sept. 30 at the century-old Al Khoziny school in Sidoarjo on the eastern side of Indonesia’s Java island. Only one student escaped unscathed, authorities said, while 95 were treated for various injuries and released. Eight others suffered serious wounds and remained hospitalized Sunday, according to Associated Press.

Police said two levels were added to the two-story building without a permit, leading to structural failure. This has triggered widespread anger over illegal construction in Indonesia.