AMMAN (Reuters) - Jordan's King Abdullah vowed to hit back "with an iron fist" against attackers who killed six army border guards with a car bomb near the frontier with Syria on Tuesday, a palace statement said.

The explosives-laden vehicle blew up a few hundred meters from a camp for Syrian refugees in a desolate area where the borders of Iraq, Syria and Jordan meet, Jordan's army said.

(Reporting by Suleiman Al-Khalidi)