The US and Russia agreed upon a ceasefire plan for Syria, which will be effective from the evening of September 12. The deal proposes a 48-hour truce, which can then be extended for the whole week.

U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov brokered the deal during a 13-hour meeting in Geneva on September 9.

The new plan has five documents, which lay out steps to secure humanitarian aid delivery, improve cooperation, assist in the political process, and ensure compliance with the ceasefire.

The negotiations aim to foster lasting peace, to launch a joint operation against ISIS and other extremist groups, to separate Syrian rebel forces from terrorist groups, and a cessation of hostilities between the Syrian government and the rebel forces.

The deal also proposes the Syrian Arab Air Force to stop flying planes over regions with a limited opposition presence. The US has also promised to weaken an al-Qaeda affiliate and terrorist organization known as Jabhat Fateh al-Sham which has joined forces with some of the US-backed opposition rebel groups, according to Al Jazeera.

The leaders were cautious about the scope of the deal, but said that this is the best agreement which has yet been arrived at in the last five years of war which has claimed over 400,000 lives.

"No one is building this based on trust," Kerry said. "It is based on oversight, compliance, mutual interest. This is an opportunity, and not more than that until it becomes a reality."

The ceasefire takes effect on the day Muslims celebrate Eid al-Adha, and the halt in fighting will allow humanitarian organizations to take the aid to war-torn pockets of the Syrian cities.

Syria's High Negotiations Committee (HNC), which represents the opposition groups, said that they have accepted the deal, and that it was up to Russia to get the Syrian regime to comply with it.

However, Lavrov said that some of the rebel groups are hesitating to carry the peace deal forward, which may make it difficult to deliver humanitarian aid to Aleppo.

The new deal hopes to unite the US and Russia and other fighting groups in Syria against ISIS and Jabhat Fateh al-Sham.