The Israeli military said early Monday its forces started attacks on Iranian targets inside Syria, killing at least 11 people.
"We have started striking Iranian Quds targets in Syrian territory," the army said in a statement, in reference to a branch of Iran's Islamic Revolutionary Guards Corps.
The military warned the Syrian regime forces against "harming Israeli forces or territory".
The Israeli army said it also targeted several of the Syrian regime's aerial defense batteries.
"We hold the Syrian regime responsible for everything taking place within Syria and warn them against targeting Israel or permitting others to target Israel from their soil," the military said.
It said it was "prepared for all scenarios and will continue operating as needed to defend Israeli civilians".
Syria's official SANA news agency confirmed Israeli airstrike inside the war-torn country.
SANA, citing a military source, said Syrian air defenses intercepted and shot down most Israeli missiles in the Syrian skies.
The UK-based information outlet Syrian Observatory for Human Rights said the Israeli attacks targeted the vicinity of Damascus International Airport and "caused substantial damage".
"The Israeli missiles managed to destroy weapons depots and military posts of the Iranians and Hezbollah in the vicinity of Damascus International Airport and the area of Al-Kiswah and Jamraya and caused substantial material damage amid information about human losses," it said on Twitter.
There was no comment from Iran on the Israeli attacks.
Monday's attacks came one day after the Israeli military said its Iron Dome defense system intercepted a missile targeting the northern Golan Heights.
Last week, Israeli Prime Minister Benjamin Netanyahu admitted that Israel had attacked Iranian and Hezbollah targets in Syria.
Israel frequently accuses Tehran of exploiting the ongoing conflict in Syria -- where Iran supports the ruling Assad regime -- to establish a permanent military presence near Israel's border.
