The rebels, in a step change of capability, are starting to use the 1,000 AT-5 Konkurs missiles supplied to them by Saudi Arabia. These have a range of 4Km and can take out a T72.
There are videos of the rebels using them to do precisely this.
Telegraph article:
Syrian rebels get first heavy weapons on the front line of Aleppo - Telegraph
The continued use of ATGMs on this scale will gradually take armour out of the equation in the conflict.
Also Iraqi Shiite militias are now poring in on the side of the rebels. Making the conflict even more sectarian.