Israeli forces carried out air strikes on outposts in Syria's Homs province in a raid early on Sunday, Syria's defence ministry said, while Western intelligence sources said a series of air bases in central Syria where Iranian personnel are based were hit in the bombings.
The Israeli military declined to comment on the reported strikes in Syria, the third since Thursday. An Israeli attack near Damascus on Friday killed two members of Iran's Revolutionary Guards, Iranian state media reported on Sunday.
Without referring to any specific places or strikes, Prime Minister Benjamin Netanyahu said on Sunday that Israel is "exacting a heavy price from terrorist-supporting regimes" outside of its borders. He was speaking to his cabinet in televised remarks.
The Syrian defence ministry said in a statement on state media that Israel launched "an aerial aggression from the direction of northwest Beirut targeting some outposts in Homs city and its countryside at 00:35 a.m." on Sunday.
A Syrian military source said on state media that the strikes caused some damage, and injured five military personnel.
Two Western intelligence sources who requested anonymity due to the sensitivity of the matter said rockets struck the T4 air base located west of the ancient city of Palmyra, and al Dabaa airport near al Qusayr city near the Lebanese border where Iranian-backed Hezbollah is dominant.
Iranian military personnel alongside fighters from Lebanon's Hezbollah are stationed at both airports and there is a strong presence of pro-Iranian militias in that area of Homs province, the sources said.
A regional intelligence source also said an underground research centre where Iranian scientists are suspected of developing missile and drone capabilities was also among the targets.
Syria denies Western and Israeli allegations that Iran, whose top military officials frequently visit Syria, has an extensive military presence in the country. It says military cooperation and arms programmes with Iran are part of a decades old strategic relationship to withstand Israel's long-term threats.
Iran says its officers serve in an advisory role in Syria at the invitation of Damascus. Dozens of Revolutionary Guards members including senior officers have been killed in Syria during the 12-year-old civil war there.
Israel has for years carried out attacks against what it has described as Iran-linked targets in Syria, where Tehran's influence has grown since it began supporting President Bashar al-Assad in the conflict.
Israel has intensified strikes in the last year on Syrian airports and air bases to disrupt what it says is Iran's use of aerial supply lines to deliver arms to militias.
Western intelligence sources have said Iran is increasingly using several civilian airports to deliver more arms, taking advantage of heavy air traffic as cargo planes offload relief aid following February's deadly earthquake.