The Syrian regime faces a bloody demise, Turkish Prime Minister Recep Tayyip Erdogan has warned, DPA reported.
"Sooner or later you will be held to account for Homs," Erdogan said in a clear warning to President Bashir al-Assad. "Bashir, it will all come back down on you."
Assad, once regarded as a friend, has lost all credibility with Ankara in the months since the unrest erupted, and Erdogan has now repeatedly called for the Syrian leader to go.
Turkey has long relied on a combination of economic and military sanctions in its dealings with Damascus, along with calls for the violence to come to an end. Arms shipments from Iran were blocked, and Ankara allowed deserters from the Syrian army to set up as the Free Syrian Army in a camp on its territory.
The Syrian National Council has established itself in exile in Turkey with Ankara's permission.
Hopes that Assad would make use of a final opportunity to institute reforms - faced with an escalation in violence in his country and increasing international pressure, and given the fate of former Libyan leader Moammer Gaddafi - have been dashed.
Ankara has over recent weeks come round to the view that Assad is playing for time by making empty promises, while carrying out yet more violent attacks on his people, as Foreign Minister Ahmet Davutoglu said before leaving for the United States on Thursday to discuss the situation.
After Russia and China blocked a United Nations Security Council resolution on Syria, Davutoglu said he intended to work on a new alliance in Washington, presenting Turkey as an honest broker in attempts to end the conflict. There had to be a new "road map", he said.
Turkey is pushing for an international conference involving all the major players, to be held in Turkey or in another country in the region.
US Secretary of State Hillary Clinton has called for the "Friends of Syria" to form a group to work together for an end to the bloodshed. Washington's initial goal is to provide aid to those trapped in the conflict zones.
Erdogan is also trying to gain Russia's support for a joint plan of action. Ankara has made clear that military intervention in Syria is not an option, thus reassuring Moscow on a key point. The establishment of a protective zone for the opposition on the Syrian side of the border, which had been under consideration, has also been set aside.
Turkey's role as Syria's neighbour and its authority in international affairs "could be needed when it comes to an all-inclusive dialogue on Syria," Russian President Dmitri Medvedev told Erdogan by phone.
While Turkey has been active on the diplomatic front and loud in its condemnation of Assad, there is no prospect of intervention in its southern neighbour.
This has drawn criticism from the Syrian opposition. "Turkey has said a lot about Syria and promised much, but done nothing thus far," a Syrian opposition spokesman told broadcaster Al Arabiya.