The 16-year-old German-Turkish boy from Frankfurt is already being celebrated as a martyr on internet forums, Die Welt newspaper wrote on Wednesday. It said there were photo montages on the web which included a picture of a young boy holding a gun which might be him.
Others were critical that such a young boy had died. "A 16-year-old should not be in Syria. Look at how his parents are doing now," one wrote.
The paper said it had photos of the dead boy in bloody clothing.
German security authorities said they were checking the veracity of reports that he had been killed and were looking at suggestions that he was just one of several under-age boys that had recently left Hesse to fight in Syria.
More than 1,000 Europeans, including at least 200 from Germany, are thought to be fighting on the side of rebels - often Islamists - against the Assad regime.
The Hesse’s interior minister Boris Rhein called last week for an early warning system to be put in place to try to prevent young Muslims being radicalized and encouraged to go to fight in Syria or other places of conflict.
A study commissioned by his ministry suggested that among the 23 men who had gone to fight in Syria, nine were still at school. Rhein said Islamists were trying to recruit specifically under-age boys for their fight.
He called for a nationwide prevention network to educate and support relatives, friends, teachers and employers so they could become more aware of the dangers. There should also be an improved system of intervention with, for example, people who return from the Syrian civil war to Germany, he suggested.