A Jordanian army officer was killed and three army personnel injured on Sunday when drug smugglers trying to enter the country from Syria fired at an army outpost along the border, a Jordanian army statement said.

The smugglers fled back to Syria, leaving behind a large cache of drugs, the army statement said. "The army will respond with all strength and resolve (against) any infiltration attempt to protect our borders and prevent anyone who dares to violate our national security."

Jordanian officials have voiced increasing alarm at a spike in attempted drug smuggling from Syria over the past year, including large quantities found hidden in Syrian trucks passing through its main border crossing to the Gulf region.

Last year the Jordanian army said it shot down a drone flying a large quantity of drugs across the border.

Jordanian officials say Lebanon's Iran-backed Hezbollah group and militias who hold sway in southern Syria are behind smuggling of one of the most popular banned drugs, a stimulant known as Captagon, which has a thriving market in the Arab Gulf. Hezbollah denies the accusations, calling them fabricated.

U.N. drug experts say Syria, shattered by a decade-long civil war, has become the region's main production site for drugs destined for Jordan, Iraq, the Gulf and Europe.

Syrian authorities have in recent months announced several major interceptions of drugs destined for Gulf markets and say they are doing their utmost to crack down on widespread production in the country.

Reuters