Washington: The new Syria ceasefire deal is rich in detail on the mechanics of ending violence in Aleppo. It says little about how the US and Russia will establish a new military partnership that is seen as key to its long-term sustainability, however.

Officials familiar with the document outline a highly technical series of requirements for both Syrian President Bashar Al Assad’s government and opposition forces. These include precise calculations, in metres, on how the sides would pull back from a key artery into Aleppo and where they would have to redeploy weaponry.

The agreement was reached last Friday after a marathon day of negotiations between US Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov. Underscoring the complexity of the new arrangement, even Kerry stumbled over some of the particulars while speaking shortly after the ceasefire came into effect on Monday.

Here are some details of the agreement, according to the US officials. They weren’t authorised to speak publicly about the still-confidential agreement and demanded anonymity.

-As of Monday, Al Assad’s government and opposition forces should have ceased all attacks with any weapons including aerial bombardments, rockets, mortars and anti-tank guided missiles.

-Sides cannot seek to acquire territory.

-They should allow rapid, safe, unhindered and sustained humanitarian access to all people in need.

-In cases when self-defence is required, proportionate force should be used.

-Two checkpoints will be established on the key Aleppo artery of Castello Road. The Syrian Red Crescent will initially operate the checkpoints, with security of no more than 20 armed personnel. Security will be determined by mutual consent of government and opposition forces. The UN will monitor the personnel, physically or remotely.

-Government forces must withdraw personnel, heavy weapons and other arms to different points away from Castello Road. In some places, tanks, artillery and mortars must be pulled back at least 3.5 kilometres. Elsewhere, soldiers with lighter weapons have to retreat at least 500 yards from the road. Other requirements concern crew-served machine guns and observation posts.

-Opposition forces also must withdraw from the road, in many places equidistant or similar to the level of pullback by government forces. East of Castello Road, their withdrawal will depend on the action of Kurdish forces. If the Kurds retreat 500 yards, the opposition forces should do likewise. Other requirements concern heavy weapons, including infantry-fighting vehicles and tanks, and crew-served machine guns.

-Opposition must make every effort to prevent Al Qaida-linked militants from advancing into demilitarised areas.

-All Syrians should be able to leave Aleppo on Castello Road, including opposition forces with their weapons. Fighters must coordinate with UN officials ahead of time.

-The US and Russia will address violations of ceasefire.

-The US and Russia will announce the establishment of their Joint Implementation Centre after at least seven straight days of adherence to the ceasefire.

-Preparatory work for the centre should have started on Monday, including information-sharing to delineate territories controlled by Al Qaida-linked militants and those controlled by opposition groups. More comprehensive delineation occurs after the centre is established.

-Starting Monday, the US and Russia should have started developing actionable targets against Daesh and Al Qaida-linked militants, so that strikes can start immediately after the centre is established. Once the first strikes occur, all Syrian military air activities must be halted in agreed areas.

-The US and Russia can each withdraw from the arrangement.