The Iran-backed Hizbollah movement said on Monday it had downed and seized an Israeli drone as it flew across the Lebanese border, a week after a flash confrontation between the arch-foes.

Israel's army said a drone it was operating "fell" in Lebanon on Sunday.

In what appeared to be a response, an air strike at "around midnight" killed 18 pro-Iranian fighters in eastern Syria, a monitor said. The Syrian Observatory for Human Rights could not confirm whether that raid was Israeli.

Later on Monday, the Israeli army said rockets had been fired from Syria but failed to reach their targets.

Hizbollah had issued a statement saying that some of its fighters "confronted with the appropriate weapons an Israeli drone" heading towards the Lebanese border village of Ramyeh overnight.