Syrian regime pounds Daraa with hundreds of missiles and barrel bombs
Hundreds of missiles and barrel bombs were unleashed before dawn after talks on rebel surrenders broke down on Wednesday, the Syrian Observatory for Human Rights said.
The Observatory said air strikes were ongoing, including on the town of Tafas in the northwest of Daraa province and on towns and villages near the Jordanian border.
Six civilians, including a woman and four children, were killed in the town of Saida, which regime ground forces were trying to take, it said.
Syria observers say the bombardment was meant to get rebels to back down after rejecting tough Russian ceasefire terms on Wednesday.
After retaking large parts of the country since Russia intervened in Syria in 2015, regime forces have set their sights on the southern provinces of Daraa and Quneitra, bordering Jordan and the Israeli-occupied Golan Heights.
Moscow has been brokering talks with rebel towns for negotiated surrenders in a carrot-and-stick strategy that Russia and the regime have used to retake swathes of territory including the Eastern Ghouta region near Damascus earlier this year.
More than 30 towns in the south have already agreed to surrender, expanding the regime's control of Daraa province to around 60 percent, double what it held before the start of the offensive.
Some rebel groups have agreed to negotiated surrenders but on Wednesday evening the remainder walked out, saying they would not hand over their heavy weapons.
Daraa is considered the cradle of the 2011 uprising against President Bashar al-Assad's rule that triggered Syria's devastating civil war.
Nearly 150 civilians have died since the assault began, according to the Observatory.
The southern offensive has also displaced between 270,000 and 330,000 people, according to the UN, many south to the border with Jordan or west to near the Israeli-occupied Golan Heights.
Both countries have kept their borders closed, despite mounting calls by human rights groups to let Syrians escape to safety.
World powers have criticised the operation for violating a ceasefire announced last year by Washington, Amman and Moscow, but that has not halted the blitz.
The UN Security Council will hold a closed-door emergency meeting on the offensive on Thursday.
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