DUBAI - Jordan's King Abdullah on Thursday called on Arab states to confront what the U.S. ally has called an alarming rise in incursions of drugs and weapons smugglers linked to Iranian militias operating in southern Syria.

Jordanian officials, like their Western allies, say the operations are controlled by Lebanon's Iranian-backed Hezbollah group and other pro-Iranian militias who control much of southern Syria after supporting Syrian President Bashar al-Assad in a civil war that has lasted almost 13 years.

"We should confront armed militant groups who commit crimes above the law, especially smuggling drugs and arms which is what Jordan has been thwarting for years now," he said, addressing Arab leaders at a summit held in Manama attended by Assad.

Most of the clandestine flow of arms into the country has been bound for the neighbouring Israeli-occupied West Bank Palestinian territory, Jordanian sources have told Reuters.

However, some weapons were intended for use in Jordan.

Syria denies cooperating with Iranian-backed militias on illicit activity, and Iran and Hezbollah say the smuggling allegations are a Western fabrication.

The kingdom foiled a suspected Iranian-led plot to smuggle weapons to help opponents of the ruling monarchy carry out acts of sabotage, two Jordanian sources with knowledge of the matter earlier told Reuters.

An official source told state news agency PETRA on Wednesday that the kingdom had in fact foiled an attempt by "foreign-backed militants" to smuggle arms into its territory, seized the weapons and detained the smugglers in March.

Over the past year, Jordan has said it has foiled many attempts by infiltrators linked to pro-Iranian militias in Syria, who it says have crossed its borders with rocket launchers and explosives, adding that some of the weapons managed to get through undetected. Iran has denied being behind such attempts.

(Reporting by Nayera Abdallah; Editing by Bernadette Baum, Alex Richardson and Sharon Singleton)