The US Army Chief of Staff has said Washington will not give up on the training programme it set up for Syrian rebels fighting the Islamic State in Iraq and the Levant group, despite a number of recent setbacks.

Earlier this month, five of the US-trained recruits were captured by the al-Qaeda-affiliated al-Nusra Front, while a sixth recruit has reportedly been killed.

Ray Odierno, who officially retires from his position as top-ranking general on Friday, said earlier this week that despite battlefield losses, the US should resume with the programme, adding that "we have a lot of work to do".

Following the captures by al-Nusra Front, reports emerged that the US-backed group, Division 30, was now refusing to fight and had accused the Pentagon of misrepresenting its mission.

The group is opposed to US air strikes carried out on al-Nusra Front fighters in recent days and says its fighters signed up to battle ISIL, not the al-Nusra Front.

At a news conference on Wednesday, Odierno said the strategy was to keep ISIL engaged in fights on multiple fronts.

"We want to try to develop capability so they have Iraqi Security Forces from the south, they have Kurds from the north, and we have Syrian rebels helping in Syria, pushing in the west," he said.

"And I still think that's something we have to work at." 

Aleppo contingent

The 54-strong rebel unit, trained and equipped by the Pentagon, was inserted into Aleppo province in mid-July as part of US plans to forge a moderate force for the campaign against the ISIL.

But despite al-Nusra's fierce hostility of ISIL, fighters from the Division 30 soon came under attack by the al-Qaeda loyalists, who believe that the US-backed battalion would end up battling them.

Al-Nusra is considered a terrorist organisation by the US and other Western countries.

Last month, US Defence Secretary Ash Carter admitted to Congress that Washington had trained no more than 60 Syrian opposition fighters to battle ISIL, far below expectations.

The programme, which launched in May in Jordan and Turkey, was designed to train as many as 5,400 fighters a year.

The US said it had only trained 60 fighters so far due to its rigorous vetting of recruits

Source: Al Jazeera and agencies