They said Abu Mousa was killed by an explosion in the town of Khan Younes in the southern Gaza Strip, but added the circumstances surrounding the explosion were still unclear.
However, the sources said they suspect the incident could have been caused by a "technical malfunction while (he was) firing a mortar towards a Jewish settlement."
Izziddine al-Qassam Brigades had not issued a statement regarding Abu Mousa, who a few months ago escaped an assassination attempt when Israeli helicopter gunships fired at his house and destroyed it.
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