At least two rockets launched from Syria have struck the Israeli-controlled Golan Heights and Israel responded with artillery fire.
The fire comes after an airstrike last week in Syria attributed to Israel that killed six members of the Lebanese militant group Hezbollah and an Iranian general.
Israel has braced for a response to that strike, beefing up its air defences and increasing surveillance along its northern frontier.
Israeli military spokesman Lt Col Peter Lerner said the fire "appeared to be intentional". He declined to comment on whether the fire may have been connected to the strike last week.
A message on Lt Col's Lerner's Twitter account said Israel "responded with artillery towards the positions that launched the attack".
The military said sirens sounded in communities in the Golan Heights earlier on Tuesday. It said that it had evacuated and closed a popular ski resort following the strike. No injuries were reported.
Israel captured the Golan Heights, a strategic plateau overlooking northern Israel, from Syria in the 1967 Mideast war and later annexed it.
Fighting in neighbouring Syria's civil war has spilled over to Israel in the past. Mortar shells have exploded sporadically inside Israeli territory since the conflict began, sometimes causing minor damage.
Israel believes most fire is errant shots, but has at times accused Syria of aiming at Israeli targets. Israeli troops have returned fire on several occasions.