The ceasefire in Syria is holding with no one reported killed in fighting anywhere in Syria during the first 15 hours of the truce. Most groups have said they will abide by its terms, though in many cases they are doing so reluctantly. Several armed opposition movements say they have been unfairly treated and see the accord as strengthening the Syrian government.

Convoys of food and urgently needed supplies will be sent to Aleppo and sixteen other besieged areas in the course of the week, if the ceasefire holds. “We are trying to get Aleppo out of the way first,” said Marwa Awad, spokesperson for the World Food Programme (WFP) in Damascus. She said there were some 20 trucks from the UN waiting to cross the Turkish-Syrian border to be followed by 20 more carrying relief supplies, the food portion of which includes sunflower oil, rice, wheat and sugar.

There are estimated to be between 250,000 and 275,000 people in rebel held East Aleppo, who are not yet starving – because the UN had pre-positioned supplies and the city has only recently been fully encircled – but are otherwise in need. WFP hopes to resupply all the besieged enclaves which it has only been able to reach intermittently over past months in the coming days.

Given the scale of recent violence, the breaches of the ceasefire so far have been minor. The Syrian state news agency SANA said rebels fired three shells at the government-held neighbourhood of Mallah in Aleppo. It also reported shelling near two important roads to the city, both much fought over in recent months: the Castello road in the northwest of the city and the Ramouseh Road in the south. Rami Abdurrahman from the Britain-based Syrian Observatory for Human Rights said there were minor truce violations in central Hama province.

The armed opposition have the biggest motive for seeing the US-Russian agreement fail because it offers them little and envisages a joint US-Russian campaign against Isis and Jabhat al-Nusra, the former affiliate of al-Qaeda that has renamed itself Jabhat Fateh al-Sham. The latter is by far the most effective fighting force of the opposition. An observer in Damascus said that “without Nusra the other non-Isis rebel groups would amount to very little militarily.” More moderate armed opposition are supposed to separate themselves from Nusra under the agreement, but this is easier said than done and Nusra is likely to move its units around quickly to avoid attack from the air.

It is much too early to predict the outcome of the ceasefire and other sections of the US-Russian agreement, which took ten months to negotiate. Much will also depend on the attitude of regional powers like Saudi Arabia, Qatar and Turkey who have armed, financed and given safe passage to the armed opposition in the past. The policy of Turkey, who has stood as a sanctuary and base area for the rebels since 2011, will be crucial and may have changed because Ankara is giving priority to its war against the Kurds rather than overthrowing President Bashar al-Assad.

Iran and Hezbollah of Lebanon have agreed to the accord but are wary of the US and Russian taking control of the agenda in Syria to the detriment of Iran and the Shia axis in general.

In pictures: Turkey launches operation in Syria Show all 9 1 /9 In pictures: Turkey launches operation in Syria In pictures: Turkey launches operation in Syria Turkish tanks driving to the Syrian-Turkish border town of Jarabulus yesterday AFP/Getty In pictures: Turkey launches operation in Syria Turkish-backed gather on the outskirts of Jarabulus, Syria, ahead of an offensive on 24 August 2016 Reuters In pictures: Turkey launches operation in Syria Turkish army tanks make their way towards the Syrian border town of Jarabulus, Syria August 24, 2016 Reuters In pictures: Turkey launches operation in Syria Turkish soldiers return from Syria to Turkey with tanks after a military operation at the Syrian border as part of their offensive against the Islamic State (IS) militant group in Syria, Karkamis district of Gaziantep, Turkey, 25 August 2016 EPA In pictures: Turkey launches operation in Syria Turkish army tanks and Turkey-backed Syrian opposition forces move toward the Syrian border as pictured from Karkamis, Turkey, AP In pictures: Turkey launches operation in Syria Turkish tanks on their way to the Turkish-Syria border during an operation against Isis on 24 August 2016 EPA In pictures: Turkey launches operation in Syria Syrian opposition fighters being transported during preparations to enter Jarabulus in Karkamis, Turkey, on 24 August 2016. EPA In pictures: Turkey launches operation in Syria An air strike hitting Isis-controlled territory near Jarabulus, near the Turkish border, on 24 August 2016. EPA In pictures: Turkey launches operation in Syria A Turkish army tank and an armoured vehicle stationed near the border with Syria. Turkish media reports say Turkish artillery has launched new strikes at Isis targets across the border AP

The US wish to influence their proxies inside Syria to abide by the agreement. Many senior US officials have expressed doubts about military cooperation with Russia and, in addition, the country is less than two months from a Presidential election.