Syrian troops have advanced on the rebel bastion of Yabrud as the country's civil war enters its fourth year, with more than 146,000 dead, millions displaced and peace efforts stalled.
Army troops were on Saturday locked in fierce clashes with rebel forces, including the al-Qaeda affiliate al-Nusra Front, after entering the town a day earlier.
The strategic stronghold is the last rebel-held town in the Qalamun region, which lies along the border with Lebanon and on the key highway between Damascus and third city Homs.
The latest fighting illustrates the intractability of the conflict that began on March 15, 2011 after popular uprisings toppled dictators in Tunisia and Egypt.
Protests erupted in Syria's southern city of Daraa after teenagers were arrested over graffiti declaring: "The people want the fall of the regime."
President Bashar al-Assad's administration reacted with force and people began to die in demonstrations that grew week after week.
Civilians took up arms, soldiers began to desert and an insurgency became full-scale civil war after the regime bombed the central city of Homs in February 2012.
Two years later, the conflict appears to have reached stalemate, with some predicting it could last another 10 or 15 years, like the 1975-1990 civil war in Lebanon.
Rebels control large swathes of the country but are fighting both the regime and an al-Qaeda-inspired group they once welcomed.
And the government holds the more densely-populated regions, seeking to protect "useful Syria" - the coast, major towns and key roads.
In Aleppo, once Syria's commercial capital, the regime has retained the city's west, while advancing around the outskirts of the rebel-held east and securing and reopening the nearby airport.
On the ground, both sides have been accused of carrying out abuses, with the regime jailing and torturing thousands and dropping barrel bombs rights groups say fail to discriminate between fighters and civilians.
Rebels too are accused of summary executions and other violations.
The human cost of the conflict has soared, with nine million people forced from their homes, creating the world's largest displaced population.
UN refugee chief Antonio Guterres on Saturday urged all nations to open their doors to Syria's refugees.
"To see Syrian children drowning in the Mediterranean today after fleeing the conflict ... is something totally unacceptable," he said.
"Borders need to be open everywhere, visa policies need to be open everywhere, family unification programs need to exist everywhere."
Aid groups are urging government and citizens to continue to donate to relief efforts with no end to the humanitarian disaster in sight.
