CNN  — 

A ceasefire between the Syrian government and opposition rebels is due to take effect at midnight tonight, potentially ending the country’s bitter five-year civil war.

Here’s what we know so far:

A nationwide deal

The Syrian regime, rebel factions, and Russian forces have agreed to the peace deal, and will lay down their weapons at 12 midnight, local time (5pm ET Thursday).

For the first time, the truce covers the whole country, and not just restricted areas, as was the case with previous ceasefires around the city of Aleppo.

Three documents were signed: the ceasefire itself, package of measures that sets out how it will be overseen, and a declaration of readiness to enter into peace talks on a political settlement for Syria.

Not everyone is included

Turkey and Russia say the deal excludes groups considered “terrorist organizations” by the UN Security Council which means ISIS and Jabhat al-Nusra. These groups could still be targeted.

However, the rebels say only ISIS is excluded – an important distinction, since territory held by al-Nusra, the al Qaeda affiliate in Syria, overlaps with theirs. Rebels fear that the Syrian regime could use the pretext of targeting al-Nusra to continue striking against them.

Russia (which backs the Syrian regime) and Turkey (which supports the rebels) have agreed to act as guarantors for the agreement – any group which breaks the ceasefire is likely to face reprisals from both Turkey and Russia, which have been on opposing sides until now.

Assad survives, for now

It is unclear what the truce will mean for Syria’s President Bashar al-Assad – whether he will step down, or a transitional government will be brought in.

Peace talks aimed at hammering out a more permanent solution to Syria’s civil war will be held in Kazakhstan next month. Syria, Russia, Turkey and Iran are expected to attend.

US sidelined

The US has been excluded from discussions in recent weeks.

However, on Thursday, Russian Foreign Minister Sergey Lavrov “express[ed] the hope that as soon as the administration of Donald Trump takes office, they will also be able to join these efforts.”

READ MORE: Truce agreed between Syrian regime, rebels

Agreement ‘fragile’

Russia says it will scale back its military operations in Syria, but will continue to support the Assad regime.

Russian President Vladimir Putin says the deal is “very fragile” and that it “demand[s] special attention and patience.”

CNN’s Muhammad Lila and Matthew Chance contributed to this report.