"Local armed factions seized control of the Nassib border crossing with Jordan, as well as nearby checkpoints and towns," Rami Abdel Rahman who heads the Syrian Observatory for Human Rights told AFP.

Earlier Jordan closed its border crossing with Syria, the kingdom's interior minister said, as the neighbouring country is gripped by fighting between armed groups and the Syrian army.

Mazen al-Faraya announced "the closure of the Jaber border crossing opposite the Syrian Nassib crossing as a result of the surrounding security conditions in Syria's south," Jordan News Agency, Petra reported.

A Syrian army source told Reuters that armed groups had been firing at Syria’s Nassib border crossing into Jordan. “Armed groups who infiltrated the crossing attacked Syrian army posts stationed there,” the source added. Dozens of trailers and passengers are now stranded near the area.

The minister added that Jordanians and Jordanian trucks would be allowed to return via the crossing, known as the Jaber crossing on the Jordanian side, while no one would be allowed to cross into Syria. 

Lebanon’s General Security Directorate also said the country is closing all land border crossings with Syria except for a main one that links Beirut with the Syrian capital Damascus.

The move came as armed groups were closing in on Syria's third city Homs on Friday, after seizing control of two strategic towns in a lightning sweep, according to the Syrian Observatory for Human Rights.

Homs is south of Hama, which armed group Hayat Tahrir al-Sham and allied militants captured on Thursday, just days after taking second city Aleppo from the government.