Jordanian border guards thwarted an attempt to smuggle large quantities of ammunition to Syria, an army source said Monday.Five people were arrested at midnight and the truck used in the smuggling operation was seized, he added.Meanwhile, the source said 755 Syrian refugees crossed the borders into the kingdom on Sunday. Jordan is the biggest host of Syrian refugees with 600,000 Syrians taking shelter in the kingdom since unrest broke out in Syria mid March of 2011.