It’s hard to imagine conditions in Aleppo getting any worse. But in the past few days, the rebel stronghold has been subjected to attacks from Syrian government forces who surround the city, aided by Russian air strikes. Gas attacks have been reported in Aleppo and the city of Saraqeb, which Syrian and Russian media blamed on rebels.

Humanitarian corridors have been created, but just a handful of Aleppo’s quarter of a million besieged have used it, fearful of a worse fate in the hands of the Syrian government.

In May, U.S. Secretary of State John Kerry set an August 1 deadline for a political transition in Syria. On Monday, Kerry put the onus on Syria and Russia to stop the cycle of violence in order to negotiate.

Is there an end in sight?