BEIRUT: Escalating violence and a vicious cycle of retaliation could leave Syria ungovernable even if a winner finally emerges from President Bashar al-Assad's battle with rebels.

Nearly a year and a half since the uprising erupted, initially as peaceful protests for reform, Assad's forces and their insurgent foes are fighting a messy conflict with no frontline and scant regard for the rules of war.

Assad has deployed air strikes and artillery to pound restive towns into submission, hitting civilian homes and hospitals. Rights groups say his forces have committed massacres. Rebels have shot or slit the throats of captured Assad supporters and hurled corpses off high buildings.

The increasing brutality of the conflict makes any prospect of reconciliation remote and exacerbates sectarian divisions between the mainly Sunni Muslim rebels, Assad's Alawite
community, and Christian, Druze and Kurdish minorities.

Assad may already be planning to exploit those divisions to ensure that, if he cannot win outright, no successor could monopolise power in the way that he and his father, Hafez al-Assad, have done for four decades.

"In order to survive, Assad and his Alawite generals will struggle to turn Syria into Lebanon - a fractured nation, where no one community can rule," said University of Oklahoma's Joshua
Landis on his blog "Syria Comment".

Landis said Assad's "Lebanon option" would be to "turn Syria into a swamp and create chaos out of (its) sects and factions... Already the Syrian army has largely been transformed into an
Alawite militia."

Opposition figures say a descent into violence and chaos will be inevitable if the outside world does nothing to stop it.

The mainly Arab and Sunni Muslim nature of the uprising means the conflict is centred on a north-south backbone of primarily Sunni populations, from Deraa in the south to Aleppo in the north.

Rather than massing their forces for a showdown with Assad's troops, the multitude of rebel brigades, mostly Syrian but including foreign jihadi fighters, have fought localised battles
with security forces which have ebbed and flowed over months.  

Areas where Assad's Alawite community are strong, including the western mountains near the Mediterranean, have been quieter, though not violence-free, while Assad appears to have acquiesced in a Kurdish grab for autonomy in the north-east.
 
U.N. investigators said this week they found reasonable grounds to declare that Assad's forces and their shabbiha militia allies had committed war crimes and crimes against
humanity, including murder and torture of civilians.

These included "unlawful killing, torture, arbitrary arrest and detention, sexual violence, indiscriminate attack, pillaging and destruction of property".  

Government forces and shabbiha militia had raped men, women and children in acts that could be prosecuted as crimes against humanity, the investigators said.

Rebels were also guilty of war crimes, including executing captured soldiers, though their violations were on a lesser scale, the investigators said.

Both government forces and armed insurgents displayed "more brutal tactics and new military capabilities" in recent months.

That greater brutality means that, barely noticed against a backdrop of battles for the capital Damascus and the commercial hub of Aleppo, around 200 people a day are now killed in towns, cities and rural districts across Syria, activists say.