Renewed assault in Syria’s southwest comes a day after rebels and Russians failed to agree on a ceasefire deal.

The Syrian government and its closest military ally, Russia, have intensified their bombing campaign in the southern province of Deraa, after ceasefire deal between rebels and Russians broke down on Wednesday.

Al Jazeera’s Zeina Khodr, reporting from Beirut, said that had air raids intensified on Thursday as government troops advanced steadily to recapture lost territory.

“The relative lull in the fighting has now been shattered following the collapse of peace talks. Syrian government and Russian planes have been targeting a number of rebel-held towns in the province,” Khodr said.

“Dozens of air strikes were reported by activists, mainly targeting the towns of Tafas in the western countryside of Deraa and in the eastern countryside of Saida.”

The UK-based Syrian Observatory for Human Rights told AFP news agency that hundreds of missiles and crude barrel bombs were unleashed by Syrian and Russian aircraft overnight through Thursday morning.

The war monitor said air raids were ongoing, including on the town of Tafas in the northwest of Deraa province and on towns and villages near the Jordanian border.

Samer Homssi, who had fled to the outskirts of Deraa with his wife and four children, described a fierce onslaught of regime air raids and shelling.

“The bombardment has not stopped for one moment since the announcement that the negotiations failed,” the 47-year-old, whose family was taking shelter in a grove of olive trees, told AFP news agency.

“We are living here in the olive trees, afraid of everything, the shelling, the insects, with no water to drink or any medical services nearby. The situation is very difficult.”

Quarter of million people displaced

The Syrian government forces retook a security checkpoint along the Jordanian border for the first time in more than three years.

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.

The fighting and air raids have already driven more than a quarter of a million people in southwest Syria from their homes, the United Nations said on Monday, seeking shelter along the borders with Jordan and Israel.

Both countries have said they will not open their borders to refugees – Jordan took in more than half a million earlier in the war – but have distributed some supplies inside Syria.

Southwest Syria is a “de-escalation zone” agreed last year by Russia, Jordan and the United States to reduce violence.

On Wednesday, Syrian armed opposition said that talks with Russia aimed at a comprehensive ceasefire in Deraa and Quneitra in southern Syria had broken down.

The Syrian Negotiations Commission (SNC) said Russia refused that Syrian regime forces and Iran-backed fighters withdraw from captured areas in order to let displaced people evacuate to rebel-held territory in other parts of Syria, as was the case in Eastern Ghouta and Aleppo.

The negotiating sides are also in disagreement over the issue of the rebels handing over their heavy weapons with Russia insisting that they give up the entirety of their arsenal in one go and rebels wanting to do so in several phases.