After a relative calm, an escalation looms on the frontier. The rebels are getting ready to confront any possible siege of Aleppo while tensions between Jabhet an-Nusra and the regime escalate south of Aleppo. The Syrian Prime Minister Wael Halaqi’s announcement that the government plans to liberate Aleppo with the help of the Russian Air Force presages more violence. It also follows several warnings from the speaker of the High Negotiations Committee Bassma Kodmani that the ceasefire is about to collapse. The High Negotiations Committee suspended its participation in the Geneva talks to protest against the escalation on the ground. De Mistura, who is scheduled to brief the Security Council on April 27, recently insisted that the ceasefire was still 70 per cent holding. The facts on the ground have changed a lot in a short time. On April 26, UN Secretary General Ban Ki-moon told reporters in Vienna he was “deeply concerned about developments on the ground.” Will the ceasefire fall apart in Aleppo?

At least two separate battles are currently underway in Aleppo: one in the south-western countryside, another in and near the city. The former was triggered by an-Nusra with the active participation of Ahrar ash-Sham whose representatives are theoretically in the Geneva Talks. Right after the partial withdrawal of Russian forces in mid-March, a group commander announced that an-Nusra would start a large scale operation across Syria. It managed to take over the strategic al-Eis highland south of Aleppo. Politically, it is trying to derail the Geneva III process by breaking the ceasefire, from which it is excluded.

An-Nusra’s intentions are clear. What, however, does Halaqi’s “liberation of Aleppo” mean? Since the early days of the conflict in Aleppo the regime has not been keen on taking back eastern Aleppo because it would involve committing large number of fighters. Liberation in this context means besieging the city until it surrenders; a brutal tactic often used by the regime. Even though government forces now surround the city on three sides, militarily, it would be an arduous task to defeat the well-fortified rebel groups, including an-Nusra, and lay siege to the city. But what the regime is after is political: it is flexing its muscles before the Geneva Talks resume.

The collapse of the truce will not just endanger the negotiations, it will also affect civilian life, which had been relatively peaceful from 27 February when the ceasefire agreement came into effect. The rebels, who during the ceasefire found time to play outdoor football and PlayStations, have tea evenings, or spend time with their families, will have to rush back to the frontlines. The Civil Defense Force in Aleppo, whose work decreased by 80 per cent, is returning to its former schedule of 50 emergency calls a day for each center because airstrikes have increased dramatically.

Doctors are again trying their best to rescue victims of indiscriminate bombardment with limited medical supplies. For the first Friday in weeks, the peaceful protests that had resumed during the relative calm did not happen because of the risk of airstrikes. In western Aleppo, the streets are again empty as its residents seek shelter from indiscriminate shelling. The death toll in Syria, which according to the Syrian Observatory during the first month of the ceasefire had decreased to its lowest since November 2011, is rising again. In short, the price of breaking this ceasefire has been high and risks getting much higher.

This ceasefire has been the most significant achievement of the negotiation process. It provides strong grounds for negotiation. It eases civilian life in most parts of Syria. Saving the ceasefire is fundamental for the continuation of the peace talks. At the moment, it is the only hope for a solution. The international community, primarily Russia, should press Assad to refrain from a major escalation. Also, local rebel groups such as Ahrar ash-Sham should stop participating in an-Nusra led operations, i.e. south Aleppo, especially given that Ahrar ash-Sham is officially part of the Geneva negotiations. Their aid to an-Nusra does not merely threaten the Geneva process, it also gives legitimacy to the regime to resume its military activities.

Map: The Guardian based on a map published by Russian media. Photograph: Yury Barmin