Syrian regime forces capture two villages in Daraa, as civilian toll climbs
The move means the northeastern part of the U-shaped piece of land the rebels hold is completely surrounded by regime forces.
"The regime achieved its most significant advance since last Tuesday" when it ramped up its bombardment of rebel positions in Daraa, the Syrian Observatory for Human Rights monitoring group said.
Regime forces in the heart of Daraa province and those in adjacent Sweida province are now directly connected.
At least 15 rebels were killed in the latest battle, the bloodiest day since the regime began ramping up its operations in the southern regions of Syria. A total of 29 rebels and 24 pro-regime fighters as well as 32 civilians have been killed since the offensive began, according to the Observatory.
Damascus turned its attention south after it retook the last pockets in and around the Syrian capital that had remained under rebel or Islamic State control.
The regime had long warned that Daraa - the birthplace of the Syrian uprising - would be next on the list.
Rebel forces also control part of the neighbouring province of Quneitra. Both provinces touch the armistice line with Israeli forces in the occupied Golan Heights.
The UN warned that up to 750,000 people were at risk as a result of the week-old offensive.
Neighbouring Jordan, which already has the world's second hightest ratio of refugees per capita after Lebanon, has warned it can not take in another mass influx from Syria.
The regime began bombarding Daraa city, but regime ally Russia, which is also providing air cover for the offensive, is leading negotiations with Syria, Jordan, Israel and the US on a settlement to avoid fierce clashes.
The assault comes despite the US, as a guarantor of the de-escalation zone in Daraa, warning it would take "firm and appropriate measures" if the regime pressed ahead with a military operation there.
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