BEIRUT, Lebanon — A tenuous truce in the Syrian countryside north of the city of Homs was shattered this month, when Russian warplanes started to attack the village of Ter Ma'aleh, killing at least a dozen people and sending most of the residents into hurried exile.
The assault was part of a wider escalation of violence across the country that has displaced tens of thousands of people in just weeks and led relief workers to warn that Syria is facing one of its most serious humanitarian crises of the civil war.
The intensity of the fighting, they say, is fueling increased desperation as a growing number of Syrians are fleeing to neighboring countries and, especially, to Europe. More than 9,000 migrants a day crossed into Greece last week, according to the International Organization for Migration, the most since the beginning of the year.
The influx has overwhelmed authorities in Greece and the northern European countries where most aim to settle.
In Homs, Hama, and Aleppo, a Syrian government offensive backed by Russian air power has reactivated dormant front lines and swept through areas that had largely escaped the fighting.
Thousands of families have fled as the government, rebel groups and the Islamic State all try to hold or capture territory. Aid groups in Turkey are rushing to provide food and other supplies to civilians, saying they are concerned that roads will be captured or cut by the new hostilities. And with winter approaching, they fear they are running out of time.
"You are really seeing these huge front lines open up, and a significant amount of bombing comes with it," said Sylvain Groulx, the head of mission for Syria for Doctors Without Borders. "There is so much displacement. We are very worried."