The Israeli military says its aircraft struck artillery positions in Syria after a projectile hit the Israeli-controlled part of the Golan Heights.

Tuesday's incident was the fifth since last week in which fighting in Syria has spilled over into Israel, and the first since a U.S.-Russian brokered truce went into effect to try and end Syria's war, now in its sixth year.

Israel has largely remained on the sidelines of the fighting, but has carried out reprisals on Syrian positions when errant fire has previously landed in Israel.

Israel is also widely believed to have carried out airstrikes on arms shipments said to be destined for the Lebanese militant group Hezbollah, a close ally of the Syrian government.

Israel captured the Golan Heights from Syria in the 1967 Mideast war.