Bashar al Assad's forces have taken vast swathes of rebel-held territory in last few months (AFP)
At least nine pro-Syrian government fighters died in an alleged Israeli rocket strike overnight in northern Syria, a monitor said Monday.
Syrian state media reported that Israel had bombed a military position in Aleppo province late Sunday.
This latest attack marks a rare Israeli attack so far north inside Syria.
The Syrian Observatory for Human Rights, a Britain-based war monitor, said that those killed included at least six Syrians.
Syrian government officials alleged that Iranian fighters were also stationed at the base.
State news agency SANA on Sunday reported a missile strike near a strategic air base but said there were no casualties.
"The Zionist enemy… targeted with its missiles one of our military positions north of the Neirab military airport, but the damage was only material," it said, citing a military source.
— Qalaat Al Mudiq (@QalaatAlMudiq) July 15, 2018
There was no immediate comment from the Israeli military, which very rarely confirms strikes on targets in Syria.
Israel has repeatedly warned it will not tolerate an entrenched presence of its archfoe Iran in the neighbouring country.
The Observatory, which relies on a network of sources inside the country, said it had recorded a wave of blasts around Neirab on Sunday night.
It said that a suspected Israeli missile strike had targeted "positions held by Syria's regime and its allies at the Neirab airport" and its surroundings.
The UK-based monitoring group added that the attacks targeted warehouses where weapons belonging to the Syrian army and Iranian militias were kept, Haaretz reported.
Suspected Israeli air strikes have hit Syrian army positions near Damascus and in the central provinces of Homs and Hama in the past but they rarely occur as far north as Aleppo.
Israel, concerned with Iran's growing presence in Syria is a threat to its security, has struck dozens of Iranian and Iran-backed positions in Syria over the course of the seven-year conflict.
Iran is a key ally of Syrian President Bashar al-Assad and backs a number of militias, including Lebanon's Hezbollah, fighting in support of Israel.
Tehran has dispatched military advisors to bolster Syrian President Bashar al-Assad's efforts to fight back a seven-year uprising against his rule.