Army defectors squared off against their former compatriots Sunday in one of the fiercest battles to wrack the country in Syria’s emerging civil war. Loyalist forces backed by tanks clashed with hundreds of army defectors in southern Syria, not far from the northern border of Jordan.

The troops were mainly from the 12th Armored Brigade based in Isa only 40 kilometers (24.8 miles) from the Jordanian border, according to the Reuters news agency. 

They stormed the nearby town of Busra al-Harir, defended by the Syria Free Army (SFA), and the nearby area of Lujah. The rock-filled hilly area north of the town has proven to be a haven for the defectors, where they are able to make camp, and from which they have been able to periodically launch attacks on government troops’ military supply lines.

“Lujah has been the safest area for defectors to hide because it is difficult for tanks and infantry to infiltrate,” explained an Isra-based activist who gave his name as Abu Omar. “The region has caves and secret passageways and extends all the way to the Damascus countryside,” he said.

Israel’s nearby Galilee, Golan Heights,as well as the Judean Desert desert landscape and Hevron Hills, are similarly rock-strewn and pocked with caves, many of which once sheltered Jewish fighters in ancient times as they hid from the Roman invaders of Israel more than 2,000 years ago. 

A general strike was also called Sunday by the groundswell of opposition sweeping the country, in hopes it would further the move to pressure President Bashar al-Assad to step down from office. Last week, a major oil pipeline from eastern Syria to the central city of Homs was sabotaged.

More than 4,000 people have died in the brutal government crackdowns that started in March with an attempt to suppress peaceful civilian protests against the Assad regime, inspired by the “Arab Spring” uprisings that had begun to sweep across the Middle East. Since that time, thousands more have also been wounded, including many tortured after being arbitrarily arrested and detained — including hundreds of children — some of whom have later “disappeared” in a manner similar to that seen in the government crackdowns of Iran.

The United Nations Human Rights Commission has charged Assad with crimes against humanity, ruling that he is to be held personally responsible for the horrific atrocities committed against his people by his troops under his command.