The bombardment on southern rebel-held areas came barely hours after the US warned the Syrian regime not to jeopardise talks on the fate of the Daraa region.
Syrian regime shelling on a rebel-held southern region has killed at least six civilians, hours after a US warning not to jeopardise talks on the area's fate, a monitoring group said on Friday.
The Syrian Observatory for Human Rights said the casualties, who included two children, were killed in shelling on two villages in the north of Daraa province.
The Britain-based monitor, which relies on a large network of sources inside Syria, said the shelling came from army positions that had recently received reinforcements.
The US state department had on Thursday warned Damascus against any military action that could scupper ongoing talks aimed at finding a settlement for the complex southern front.
"We reiterate that any Syrian government military actions against the southwest de-escalation zone risk broadening the conflict," spokeswoman Heather Nauert said in a statement.
"We affirm again that the United States will take firm and appropriate measures in response to Syrian government violations in this area."
Highest toll since agreement
The United States, Russia and Jordan agreed to a de-escalation deal in the southern province, and negotiations are continuing in a bid to reach a deal that would remove the need for an offensive by the regime.
The Observatory said Friday's shelling had caused the highest civilian toll since the de-escalation deal, reached almost a year ago.
The region borders Jordan and the Israeli-annexed Golan Heights.
Rebel groups, who still control about two-thirds of Daraa, have so far refused to negotiate with the Syrian regime.
In an interview with Iran's Al Alam television channel earlier this week, Syria's Bashar al Assad said contacts were ongoing between Russia, the US and Israel over the southern front.
"We are giving the political talks a chance, but if they fail, there will be no choice but liberation by force," he said.
The regime wants rebels to withdraw from the area either by force or under a deal similar to those that saw armed groups transferred from their bastions in and around Damascus.
Also at stake in the current talks are the future of a US military base in southeastern Syria and the presence of Iranian and allied forces in southern parts of Syria near the border with Israel.