The development of de-escalation zones aimed at reducing violence in Syria have been cautiously welcomed. Like other peace efforts, there was initial fighting soon after the measures were supposed to have taken effect.

But on Saturday (6 May) the situation appeared calmer. The zones – spread across Idlib, Homs, Ghoutta and territory close to the border with Jordan – were created by Russia, Turkey and Iran following diplomatic talks in Astana, Kazakhstan. No Syrian representatives were party to the agreement.

Despite still being fully worked out, the Astana talks are the first which have seriously proposed the implementation of no-fly zones and the presence of foreign troops monitoring the de-escalation territories.

Why are ceasefires not adhered to?

Previous ceasefire agreements in Syria have mostly failed. The Syrian conflict is multi-dimensional, with numerous internal and external actors holding divergent agendas, many of whom do not respect the wishes of international institutions such as the UN. Many groups are small and autonomous, reacting largely to local circumstances.

In the past, there have also been no so-called 'boots on the ground' – infantry troops – to enforce peace deals.

These factors, coupled with the ferocity of the conflict, have weakened previous efforts to reduce violence.

In addition, groups identified as terrorists, such as Isis or the al-Qaeda-aligned Tahrir al-Sham (formerly al-Nusra) are also not involved in peace negotiations, destabilising their prospects. Tahrir al-Sham is reportedly present in all of the proposed de-escalation zones and often work with other rebel groups.

Fighting "terrorism" is also a caveat commonly employed by the Assad government and Russia. It has broad implications and is often used to define any rebel group opposed to the Syrian government, regardless of its ideology.

Has this been tried before?

While the Syrian peace process has been ongoing almost since the war begun, there have been three major attempts at reducing or ending hostilities in Syria.

In February 2016, a ceasefire backed by the UN, US and Russia held for several days. However, reports of sporadic fighting in various places quickly emerged until the cease-fire became one in name only. By July, it was internationally recognised as a failure.

In September 2016, the US and Russia struck a deal aiming to reduce fighting between the Syrian government and US-backed rebels, in order to allow aid to reach civilians. But there was little confidence in it, aid failed to reach civilians and fighting continued. It fell apart within a week after an aid convoy was hit by a Syrian or Russian air strike.

The Astana talks led to the implementation of a third attempted national ceasefire, brokered by Russian and Turkey, involving some rebel groups. Again, fighting broke out soon after the truce was declared but the UN maintained in January it was mostly holding. Russia announced it would be reducing its military capabilities in Syria but critics said this was a mostly symbolic move. The ceasefire disintegrated by February.