AMMAN (Reuters) -Jordanian soldiers killed 27 smugglers as they tried to cross the border from Syria with large quantities of amphetamines during a snowstorm, an army spokesman said on Thursday.

       Others also carrying drugs fled back into Syria during the attempt, one of an increasing number of such incidents over the past year that had led the army to toughen its rules of engagement with smugglers.

       The army has also found large quantities of drugs - mostly commonly an amphetamine known as Captagon - hidden in Syrian trucks passing through Jordan's main border crossing to the Gulf region.

       Jordanian officials say Lebanon's Iran-backed Hezbollah group and militias who control much of southern Syria are behind the surge in smuggling. Hezbollah denies the accusations.

       Captagon has a thriving market in the Gulf, and U.N. drug experts say Syria, shattered by a decade of civil war, has become the region's main production site for drugs also destined for Jordan, Iraq and Europe.

       (Reporting by Suleiman Al-Khalidi; Editing by Toby Chopra and John Stonestreet)