MOSCOW (Reuters) - Russia said on Wednesday that it strongly backs the actions of the Syrian leadership to counter an offensive by what it said were terrorist groups receiving support, including drones and training, from outside the country.

Syrian and Russian jets are stepping up strikes on opposition forces in northern Syria in retaliation for the sudden offensive that has cost the regime control of the country’s second largest city, Aleppo.

The surprise offensive on Aleppo by Syrian rebel groups has left the US in the difficult position of not fully supporting either side while also maintaining a force posture of nearly 1,000 troops in Syria as part of the ongoing mission to fight ISIS.