YEREVAN, JULY 23, ARMENPRESS: The top US military officer has outlined the costs, risks and benefits of possible American military involvement in the Syrian conflict, reports Armenpress referring to BBC.

Joint Chiefs of Staff chairman Gen Martin Dempsey offered five military options, including limited strikes and establishing a no-fly zone.

But he said using force in Syria would be "no less than an act of war" and could cost the US billions of dollars.

Washington has so far ruled out military intervention in Syria.

Its role in the conflict is currently limited to delivering humanitarian aid to Syrian refugees in neighbouring countries and providing non-lethal help to the Syrian opposition.

In an open letter to senators, Gen Dempsey analysed five military options the US military could potentially undertake in Syria: training, advising and assisting the opposition; conducting limited strikes; establishing a no-fly zone; creating buffer zones inside Syria; controlling Damascus' chemical arms.

Gen Dempsey estimated that the first option would cost about $500m (£325m) a year, while each of the other four actions would require roughly $1bn a month.

"The decision to use force is not one that any of us takes lightly. It is no less than an act of war," he wrote in the letter.

Gen Dempsey acknowledged that the outlined actions would strengthen the opposition and put more pressure on President Bashar al-Assad, but he warned the US should learn from its previous interventions, as in Afghanistan and Iraq.

"We have learned from the past 10 years, however, that it is not enough to simply alter the balance of military power without careful consideration of what is necessary in order to preserve a functioning state," he said.