Here are key developments in Turkey's increasingly central role in resolving the Syria conflict, having joined Russia in negotiating the ceasefire which came into force on Friday:

- Ankara drops Assad - 

In September 2011 then Turkish prime minister Recep Tayyip Erdogan, who had previously described Syrian President Bashar al-Assad as a friend, says: "The Syrian people do not believe Assad, and I do not either."

Siding with the West six months after peaceful protests against Assad were brutally put down, Ankara puts diplomatic pressure on its neighbour alomg with other players before imposing sanctions on Damascus in November 2011.

- Hosts Syrian opposition - 

In July 2011 Syrian army colonel Riyadh al-Assad  sets up a Free Syrian Army operating out of Turkey to fight the regime.

In October, after several meetings on Turkish soil, Syrian opposition leaders meeting in Istanbul announce the creation of a broad-based Syrian National Council.

In November 2012 Turkey recognises the Council as "the legitimate representative of the Syrian people".  

- Fears autonomous Kurdish region  - 

In September 2014 Islamic State jihadists attack the Syrian border town of Kobane and enter. Kobane becomes the scene of urban guerrilla fighting.

Ankara, accused of letting IS fighters reach Syria via Turkish territory, rebuffs pressure by western allies to intervene militarily and help Kurdish forces against the jihadists.

Turkey has regularly voiced concern over the possibility of an autonomous Kurdish region in Syria led by militias it considers close to the Kurdistan Workers' Party (PKK), which it considers a terrorist group.

In late January, Syrian Kurds backed by international air strikes retake Kobane.

- Joins anti-jihadist coalition -

On July 20, 2015 the Syrian conflict spills into Turkey with an attack blamed on IS fighters in the border town of Suruc that kills 34 people.

Erdogan launches a "war against terrorism" aimed at both the PKK and the IS.

In August, Ankara joins the US-led coalition and tightens airport and border checks. Jihadist cells are dismantled after several attacks blamed on the IS, including one which kills 103 people at Ankara's central railway station in October.

- Makes up with Moscow -

On August 9, 2016 Erdogan meets Russian President Vladimir Putin in Saint Petersburg to seal a reconciliation with Moscow, which has backed Assad. Ties had deteriorated after a Russian fighter plane was shot down by the Turkish air force the previous November.

Putin is one of the first world leaders to call Erdogan following a failed coup attempt in Turkey on July 15.

On August 20, Turkish Prime Minister Binali Yildirim says Assad can remain temporarily during a transition period because "he is one of the actors today no matter whether we like it or not".

- Turkish tanks into Syria -

On August 24, Turkish troops launch Operation Euphrates Shield in Syria to drive out the IS, as well as Kurdish militias.

Turkish tanks and opposition fighters drive the IS out of the key Syrian border town of Jarabulus.

- Takes lead with Russia -

On December 7 Prime Minister Yildirim, speaking a day after visiting Moscow, says Turkey's intervention is "in no way connected to what is happening in Aleppo" where they regime is carrying out a devastating offensive, " and in no way connected to changing the regime in Syria". 

On December 22 the Syrian regime declares it has full control of Aleppo city, after tens of thousands of civilians and rebel fighters are evacuated under a deal sponsored by Russia, Iran and Turkey.

On December 29, after several meetings in Turkey between Russian envoys with rebel representatives, Putin announces a ceasefire deal between the regime and the armed opposition. It is the first time that Turkey sponsors such an accord.

Source: AFP