The army backing the disputed Ivory Coast President Laurent Gbagbo calls on youths to enlist to help fight in the battle against his rival, Alassane Ouattara.

A public rally in support of Laurent Gagbo in Abidjan (Getty)

The call - for "young patriots...to pick up weapons to go and fight" - has fuelled fears that child soldiers, who were widely drafted into the front-line during the last outbreak of civil war eight years ago, are becoming a growing feature again as fighting intensifies.

Laurent Gbagbo - who refused to step down as President despite having been declared by the United Nations as the loser of last year's elections - has come under increasing pressure both internally and externally.

On Wednesday, the UN Security Council agreed to impose sanctions on the regime - including freezing its assets, banning travel and an embargo on the use of heavy weapons in the main city of Abidjan.

At the same time, Alassane Ouattara's forces have been making steady gains, including the capital, Yamoussoukro, and the major cocoa port of San Pedro.

Corinne Dufka - senior Africa researcher for Human Rights Watch - told Channel 4 News: "I've interviewed from recruitment camps in the past and child soldiers have been a big problem. I can't say if they are using them now. The UN have documented small scale use of child soldiers, but it is simply too difficult to monitor right now."

Speaking to Channel 4 News from an undisclosed location in Ivory Coast a spokesman for Ouattara - Konate Siratugui -denied that Ouattara's troops were using child soldiers in the conflict, but claimed that Gbagbo was doing so.

"(Child soldiers) are flooding in from the cocoa fields straight into Gbagbo's ranks, he is exploiting them because they are poor and have nowhere to go." Ouattara spokesman Konate Siratugui

"They are flooding in from the cocoa fields straight into Gbagbo's ranks, he is exploiting them because they are poor and have nowhere to go, he has always done this," said Siratugui.

During the 2002-3 civil war all armed protagonists diverted hundreds of millions of dollars from cocoa fields to fund a conflict marked by torture, sexual violence, and cannibalism.

Mike Davies - from the campaign group Global Witness - told Channel 4 News that vulnerable children had been recruited by several militia forces in the past, meaning their use in the current conflict "can't be ruled out".

Cocoa-fuelled conflict

Four million of Ivory Coast's 17 million inhabitants work in some aspect of the cocoa trade. This includes 200,000 children, of which an estimated ten per-cent may have been trafficked according to the International Labour Organisation.

During the 2002-3 civil war cocoa brought about 1.4 billion dollars of revenue annually to the south, controlled by the government of President Laurent Gbagbo, according to official figures. In the north, overseen by Ouattara's rebel Forces Nouvelles, yearly cocoa revenues were thought to bring in around 30 million dollars per year.

Since the disputed elections international sanctions have been placed on Ivory Coast's cocoa trade in an effort to limit Laurent Gbagbo's funds.

But Global Witness say sanctions may not working, and that a highly sophisticated smuggling operation is underway to channel cocoa via other countries.

Mike Davies said that ""the main armed protagonists have a history of seizing cocoa revenues, in 2002 they had a very questionable record of extorting tax revenues to pay for their war efforts."

Global Witness currently has to rely on a range of unverified reports but "there is no reason to think that highly orchestrated smuggling has stopped", he said.

"For the FN there have been supply routes across porous borders to Burkina Faso and Togo. Our information suggests Togo has seen a massive increase in it's exportation of cocoa disproportionate to its ability to produce it," added Mike Davies.

"It would be very surprising if Gbagbo and his allies were not looking to generate funds through cross-border trafficking given the difficulties they now face in shipping cocoa out of Abidjan and San Pedro in the light of the EU sanctions."