Muhammad Qunneita, 31, from Shati refugee camp in the Gaza Strip, had been in Syria for four months, his brother told Ma’an.
Rebels told Reuters on Saturday Qunneita was killed in fighting around Aleppo airport where he had been helping to train Arab and Muslim fighters. Activists in Syria also said he had been a prominent figure in Hamas’ Al-Qassam Brigades.
After Qunneita died on Friday, Hamas-affiliated news site Palestine Now described him as a Al-Qassam field commander, quoting a military official in Gaza.
He had trained several rebel brigades during his time in Syria, and was fatally wounded during the storming of Idlib airport on Thursday, the report said.
But a Hamas source in Gaza told Reuters Qunneita had left the Hamas brigade and joined a jihadi group before leaving for Syria to fight there.
The exiled leadership of Hamas was based in Damascus until earlier this year, when officials from the Sunni Islamist movement, which sympathizes with the uprising against Assad, quietly pulled out.