A teenager selling coffee in the northern Syrian city of Aleppo was arrested by Islamist rebel fighters for insulting the Prophet Mohammed, beaten and then executed in front of his family, a watchdog group claims.

The boy, Mohammed Qatta, 14, reportedly refused to give a customer coffee, the Syrian Observatory for Human Rights reported Sunday.

"Even if [Prophet] Mohammed comes back to life, I won't," the boy said, who was known by his nickname "Salmo."

Extremist rebels driving past in a black car overheard the comment, the opposition Aleppo Media Center said. Qatta was taken away by the fighters and later brought back, his head wrapped with his shirt and his body covered with marks from whipping.

The rebels then read out the boy's sentence - not in a Syrian accent, but in classical Arabic. They accused the boy of blasphemy and told the crowd - which included the boy's parents - that anyone who insulted the Prophet would suffer a similar fate.

Qatta was then shot in the mouth and neck. A graphic photo was released late Sunday of the dead boy clearly showing wounds that matched the reports.

The boy's parents confirmed the accounts in an interview posted online on Monday by the Aleppo Media Center. In it, his father stoically recounted the execution while his mother wailed.

"Why did they kill my son," she cried. "We are not for or against anybody in this conflict, may God take revenge on them."

The Islamists and their group have yet to be identified. Large swathes of rebel-held Aleppo are under the control of al Qaeda-linked rebel groups who have set up Sharia courts and welcomed large numbers of foreign fighters into their ranks. The United States and its allies have struggled with the question of whether to arm an extremely fragmented opposition force whose strongest elements have pledged allegiance to al Qaeda.

Aleppo is expected to become of the focal point of Syria's two-year civil war in the coming days as Syrian forces look to take back full control of Syria's most populous city in a new offensive reportedly dubbed "Northern Storm."

ABC News' Nasser Atta contributed to this report

These are the people William Hague wants to Arm

a watchdog group claims.

Those people who did that are rebels, murderers and criminals. They are not religious, they just claim to be.

They need to be brought to justice like any other terrorist criminal.

lol... these are the people the US is funding right now... can anyone say hypocrisy?....

The US has always funded and backed Al Qaeda. The CIA trained him to be a terrorist.

That's why I'm against paying taxes. I don't want to fund terrorists.

Not just the US, France and England as well.

I agree. The death of this teenager is clearly the fault of the US. We should stop funding any side and let the world live in peace.

good one!

I think if the Banksters would stop funding wars, there would be no more wars.

not just bankers, the oil cartel has a big stake here too... and, on a side note, the fall of Damascus is a big part of the biblical apocalypse..

I said BANKSTERS.

I don't believe in the "Biblical Apocalypse."

What a bunch of hogwash.

maybe... but no matter the prophet or prophecy, it still seems like we are heading towards something...

Yes we are.