Lebanon's Hezbollah leader Sayyed Hassan Nasrallah speaks via a screen during a protest in Beirut's southern suburbs, Lebanon December 11, 2017. (Reuters Photo)

DUBAI, Dec. 12 (Xinhua) -- Former U.S. Secretary of Defense Robert Gates said Tuesday that there might be an all-out war between Israel and Lebanon's Iran-backed Shiite militia Hezbollah in 2018.

He made the remarks at the one-day annual Arab Strategy Forum held in Dubai in its 10th edition.

As Hezbollah had helped the Syrian regime defeat the Islamic State (IS) group, "this might encourage the militia to step up attacks on Israel," said Gates, who served under the two U.S. Presidents George W. Bush and Barack Obama.

Israel in return might feel that "Hezbollah becomes a problem to deal with," he added.

Hezbollah has been supporting the Syrian regime under President Bashar al-Assad in its fight against IS and other militia groups in Syria through sending fighters and weapons.

In the summer of 2006, Hezbollah and Israel fought a 34-day war and have since exchanged sporadic fire along the Lebanese-Israeli border.

Gates said he expects the tension to rise between Shiite Iran and Saudi-led Sunni Arab states "as Iran continues in trying to increase its influence and meddling across the Middle East."