Ayman Safadi, Jordan's foreign minister, said in a tweet on Friday that the return of the tens of thousands of displaced Syrians in southern Syria is the kingdom's top priority and he had discussed "practical guarantees" with concerned parties.
This Saturday, June 30, 2018 photo provided by Nabaa Media, a Syrian opposition media outlet, shows people who fled from Daraa, walk outside their tents near the Syria-Israel border, southern Syria.
The rebels in southern Syria once received significant backing and support from the USA that has and all but dried up over the past few years.
Both countries say they will not open their borders, but have distributed some supplies inside Syria.
'The Assad government wants both Daraa city and the Nassib border crossing, ' said Nicholas Heras, an analyst at the Washington-based Centre for a New American Security.
Dark smoke rose over areas held by Syrian rebels near the border with Jordan as President Bashar al-Assad's Russian allies unleashed heavy air strikes and government forces sought to advance on the ground.
Ibrahim Jabbawi, another spokesman for the rebels' southern operations, confirmed the agreement on a ceasefire, the surrender of heavy weapons, and the rebel handover of the frontier road with Jordan.
The Syrian Observatory for Human Rights said on Saturday that the regime now controls about 70 percent of Daraa province.
Rebel territory in southern Syria was already included in a ceasefire agreed past year between Washington, Amman, and Moscow, but that did little to halt the regime's attack.More news: Belgium knocks soccer powerhouse Brazil out of World Cup
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"They (rebels) destroyed the town, God will punish them", said a 50-year-old villager who returned to check on her home.
Although local communities in Syria have opened their doors to take in numerous displaced, most are forced to live in open spaces or in makeshift shelters that offer little safety and protection from the elements, he added.
"Cars carrying Russian military police and representatives of the Syrian government's border administration entered the Naseeb crossing without a fight", observatory head Rami Abdel Rahman said.
However, Mr Assad set his sights on retaking them after defeating rebels in the Eastern Ghouta region outside the capital Damascus in April.
The UN refugee agency (UNHCR) on Thursday warned that 320,000 people have been displaced by increased hostilities in southwest Syria while another 750,000 risk being caught in the crossfire.
The UN's refugee agency says that around 60,000 Syrians have gathered near the border.
Mr Assad is also aiming to recover control of rebel-held areas of Quneitra province at the frontier with the Israeli-occupied Golan Heights.
An opposition commander with Jaish al-Janoub told Syria Direct on Monday that rebel fighters were still "stationed on the frontlines" with pro-government forces, but were not sure what would happen next.