The Syrian army says it has shot down an Israeli warplane and drone in Syria after an Israeli attack on a Syrian army position.
It comes less than 24 hours after a ceasefire came into effect in an effort to end Syria's war, now in its sixth year.
Earlier, the Israeli military said its aircraft struck artillery positions in Syria after a projectile hit the Israeli-controlled part of the Golan Heights.
The incident was the first since the US-Russian brokered truce went into effect at sunset on Monday, local time.
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.
The Israeli military has denied any of its aircraft were shot down in Syria, saying two missiles were fired during an air strike but missed.
