Jordan closed its main border crossing with Syria on Monday after two days of fighting there between Syrian troops and rebel fighters, Jordan's information minister said.
Border traders said passengers were turned back at the Jordanian border crossing of Jaber and prevented from entering in the first such closure of the crossing since the revolt against President Bashar al-Assad's rule started two years ago.
"The border post is effectively closed because there have been clashes since yesterday and they are continuing," minister Samih Maaytah told Reuters.
The crossing is a thoroughfare for passengers and was transit route before the Syria conflict for hundreds of trucks daily carrying goods to Turkey from the Gulf and vice versa.
Situated near the Jordanian border, Syria's southern Deraa province is a vital battleground. Rebels in the last month have stepped up fighting for control of the border area and Deraa town after gaining territory in the countryside and capturing several army bases.
They have also overrun several towns near the Israeli-occupied Golan Heights, fuelling tensions in the sensitive military zone.