Syria intervention 'could cost US billions of dollars' The US announced in June it would provide additional military support to vetted groups of Syrian rebels, and this week administration officials said it had overcome concerns from Congress over how to safeguard against weapons falling into the hands of Islamist militants fighting the regime. Rebel support groups say the deliveries - including light arms and anti-tank weapons, but not surface to air missiles - could now start as early as next month. With the UN declaring the Syrian refugee crisis to be the worst since the Rwandan genocide nearly 20 years ago, pressure is building in some quarters for the US to take more direct action to assist the rebels. Gen Dempsey said training the rebels in tactics and weapons usage would cost $500 million (£325 million) a year and could require "several thousand" US troops on the ground which also risked inadvertent association with war crimes as the conflict descended into cycles of revenge. The next level would be "limited stand-off strikes" to degrade the Assad military, but Gen Dempsey said these would require "hundreds of aircraft, ships, submarines, and other enablers" with the costs running into billions and the risk of scattering Assad's forces. Establishing a no-fly zone over Syria - a popular course among those advocating intervention - would cost $1 billion a month, he wrote, and would risk US aircraft while potentially doing little to degrade Assad forces which relies "overwhelmingly" on mortars, artillery and other surface weapons. Creating a buffer zone for training rebel forces in Jordan or Turkey would also cost $1 billion a month and while improving rebel military capabilities risked refugee camps coming under retaliator shell fire while creating potential bases for extremists groups like the al-Qaeda linked Nusra Front. Lastly, efforts to control chemical weapons, including commando raids by "thousands of special operations forces" would also require establishing a no-fly zone and cost billions more but, even then would control "some, but not all" of the Assad regime's "massive" stockpiles of chemical weapons. "Should the regime's institutions collapse in the absence of a viable opposition, we could inadvertently empower extremists or unleash the very chemical weapons we seek to control," he also warned. Advocating a "regional approach" that drew in US allies in the region, Gen Dempsey concluded by supporting the current position of the Obama administration which has long been reluctant to deepen involvement in Syria. We should help develop a moderate opposition - including their military capabilities - while maintaining pressure on the Assad regime.