Stills were published on the Arabic-language al-Shamouk jihadist website, reported Qulliam, a London-based "counter extremism" think tank.

It said the movie would show "heroic acts" including "armed engagements".

But a US government adviser on counter-terrorism expressed doubt that such a cartoon was really being made.

The post on the al-Shamouk website was authored by someone calling himself Abu al-Laith al-Yemen, Quilliam said.

It quoted him as saying: "The cartoon movie al-Qaeda in the Arabian Peninsula is a very exciting story that tells the facts about who let down the Islamic religion and the Prophet...

"It aims to catalyse the youth and the children to follow the steps of Islamic jihadist figures. It includes real incidents and features heroic actions by the mujahideen in the Prophet's peninsula.

"These incidents include raids, armed engagements and assassinations."

The film was an "alternative to the poison that is broadcast by other TV channels to our children and youth", he added.

The contributor included four images apparently taken from the film, which he claimed was in the final stages, and asked website users to give their reaction.

"Whether or not this movie actually appears, this shows a significant development in al-Qaeda's attitude to the media and to recruitment," said Noman Benotman, a former jihadist and Quilliam analyst.

"They are trying out new methods to make terrorism exciting to young people and even to children."

But the plan "may backfire", Mr Benotman added.

"Many Muslim parents will see this as a direct attempt by al-Qaeda to create divisions within families and to undermine the authority of parents."

He said the purported movie could also be evidence that a discredited al-Qaeda was having to resort to "gimmicks".

Will McCants, a scholar of militant Islamism and US government counter-terrorism adviser, told readers of his Jihadica website he was "very sceptical" it was a real product.

"But if it's legit and anywhere near like the purported screen shots and promotional banner below, it would indicate that [al-Qaeda in the Arabian Peninsula] is becoming even more sophisticated in its efforts to reach out to youth.

"Now they just need some action figures."