The animated GIF above details the strategic lay of the land in the area around the Syrian city of Aleppo, from the beginning of February to Thursday. The city, once Syria's most populous urban center and commercial capital, sits toward the bottom middle of the map.

In less than two weeks, troops and allied militias loyal to Syrian President Bashar al-Assad — represented by the beige colors — have managed to almost encircle the beleaguered rebel positions in Aleppo and cut off their supply lines to Turkey.

The area in green is loosely controlled by rebels; to the north of Aleppo, the vital corridor to Turkey was increasingly under threat from both the regime forces and the Kurdish militias (represented in yellow). Over the past week, that link was severed, raising the prospect of a grim and deadly siege of the remaining rebel-held areas of Aleppo.

Here's a wider angle map of Syria made by The Washington Post before the regime's latest gains.

AssadAleppoWaPO

As WorldViews and its colleagues have reported in the past two weeks, the capture of Aleppo would mark a potential turning point in the brutal five-year-long Syrian civil war. It would signal perhaps the most important military victory for the Assad regime and has already prompted a new, desperate rush of refugees to the Turkish border.

Assad's campaign to retake Aleppo was significantly boosted both by the involvement of Iranian-backed militias fighting alongside government forces on the ground, as well as months of withering airstrikes carried out by Russian fighter jets. Moscow's bombardment shifted the strategic calculus in Syria, with U.S. officials now grappling with the reality that the embattled Syrian leader may be much harder to dislodge.

"The Russian reinforcement has changed the calculus completely," Lt. Gen. Vincent R. Stewart, head of the Defense Intelligence Agency, said in Senate testimony cited this week by The Post's Greg Miller. Assad is "in a much stronger negotiating position than he was just six months ago,” Stewart said. “I’m more inclined to believe that he is a player on the stage longer term than he was six months to a year ago."

Assad's increasingly comfortable position (and the rebels' conversely dire state) has shadowed planned U.N.-brokered talks on the conflict and may likely derail them.

Meanwhile, a host of governments are still struggling to figure out how to vanquish the Islamic State, an extremist organization whose territory is marked in black on both maps above.

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