Eyewitnesses said that a huge blast rocked near Musab Ibn Umair Mosque in Al-Bureij refugee camp.
Gaza Health Ministry spokesman Ashraf al-Qadra told Anadolu Agency that the blast left a 27-year-old man dead and two injured.
Security sources said that an investigation has been opened into the blast.
Earlier in the day, a 25-year-old man was killed and two others were injured in a blast in the Green Hill area, east of Al-Bureij refugee camp, medical sources said.
Gaza police spokesmen Ayoub Abu Shaar said that the security agencies had opened a probe into the incident.