Surabaya, Oct. 6 -- Five people were injured in an unknown explosion in the San Antonio shophouse complex in Surabaya, East Java, on Tuesday morning, while at least 20 buildings in the surrounding area were reportedly damaged.

An officer of the Surabaya Regional Agency for Disaster Countermeasures (BPBD), Tito, said the victims had been evacuated to the hospital for medical treatment.

"The victims have been evacuated and rushed to the hospital for initial treatment," he said.

According to preliminary information, four victims were initially taken to Surabaya Haji Hospital and one to Mitra Keluarga Kenjeran Hospital.

The Surabaya Command Center officials later reported that the victims were transferred to Dr. Soetomo Regional General H...