Geneva, Jul 5 (IANS): 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 High Commissioner for Refugees Filippo Grandi said he was gravely concerned for the welfare of civilians and humanitarian aid workers in Daraa province, a region of opposition-held Syria on the Jordanian border.

The border is currently closed but it has been the scene in recent weeks of an escalating government campaign of airstrikes and artillery fire, Efe news reported.

"An estimated 750,000 lives are in danger. More than 320,000 people are now displaced. Most are living in dire and insecure conditions, including some 60,000 people camped at the Nasib/Jaber border crossing with Jordan," Grandi said.

"There are large numbers of women and children among the displaced. There are elderly, injured and sick people and I am especially concerned about them," he continued, adding that the volatile security situation in the region was hampering UN efforts to deliver humanitarian and assistance.

He said the conflict left many residents of Daraa with no option but to seek shelter in neighbouring Jordan.

The Hashemite Kingdom, which has taken in roughly one million refugees since the outbreak of civil war in Syria, recently announced the closure of its frontier.

Grandi thanked Amman for its assistance and urged it to once again offer temporary relief to those caught in Daraa violence.

He said the international community should support Jordan and warned that thousands of lives would be lost if urgent action was not taken.