Three Palestinians were killed Wednesday in a bomb-making accidental blast in southern Gaza Strip city of Khanyounis, medical sources said.

Spokesman for the Hamas-run ministry of health Ashraf al-Qedra told Xinhua that three people were killed and four others injured in a blast that has shaken the city.

Local witnesses said the three men were militants and were killed in a bomb-making accident.

Meanwhile, an Israeli army spokeswoman told Xinhua that the Israeli military has no connection with the explosion.

Gaza-ruling Hamas police has started an investigation into the incident. Such incidents happen repeatedly in the Gaza Strip where militants get killed while preparing home-made rockets or bombs to be used during the conflict with Israel.