The UK-based Syrian Observatory for Human Rights said 36 Syrian troops, seven Hezbollah fighters, and a Syrian member of an Iran-backed group were killed, and dozens of people were wounded. It called it the deadliest such attack in years.

The Syrian army says Israeli airstrikes on Friday near the northern city of Aleppo killed or wounded “a number of” people and caused damage. The UK-based monitoring group says the strikes left 44 people dead, most of them Syrian soldiers.

Syria’s defence ministry said Israeli planes targeted several sites in the Aleppo countryside at 01:45 a.m. on Friday (22:45 GMT Thursday), killing a number of civilians and military personnel.

It said the air strikes were carried out “in conjunction with” drone attacks by “terrorist organisations” against Aleppo city and its surrounding area, though it did not give any further information.

The Israeli military said it would “not comment on reports in the foreign media”.

The UK-based Syrian Observatory for Human Rights, an opposition war monitor, said Israeli strikes hit missile depots for Lebanon’s militant Hezbollah group in Aleppo’s southern suburb of Jibreen, near Aleppo’s international Airport, and a nearby town that houses a military facility.

The observatory, which has an extensive network of sources in Syria, said at least 36 Syrian troops, seven Hezbollah fighters, and a Syrian member of an Iran-backed group died. It added that dozens of people were wounded.

“It is worth noting that this is the highest death toll ever among regime forces in a single Israeli attack in Syrian territory,” the group said.

Hezbollah added that Israeli strikes also targeted air-defence forces sites in al-Saferah, while explosions were heard in the Kafr Joum area, in western Aleppo.

There was no immediate statement from Israeli officials on the strikes. Israel, which has vowed to stop Iranian entrenchment in its northern neighbor, frequently launches strikes on Iran-linked targets in Syria but rarely acknowledges them.

Hours after the strikes, Israel’s military said it had killed a senior Hezbollah figure in an air strike in Lebanon.

Ali Abed Akhsan Naim was a deputy commander of the group’s missiles and rockets unit, the Israel Defense Forces (IDF) said, and was responsible for conducting and planning attacks on Israeli civilians.

Video released online by Israel showed a moving vehicle, which he was said to be travelling in, exploding after being struck by a missile.

The IDF said the strike took place in the Bazuriyeh area, east of the port of Tyre.

Hezbollah has not yet commented on the reports.

Israel has launched hundreds of airstrikes on targets in Syria since the civil war began there in 2011, as it seeks to cut off Hezbollah supply routes to Lebanon.

Aleppo, Syria’s largest city and once its commercial centre, has come under such attacks in the past that led to the closure of its international airport. Friday’s strike did not affect the airport.

The strikes have escalated over the past five months against the backdrop of Israel’s war in Gaza and ongoing clashes between Hezbollah and Israeli forces on the Lebanon-Israel border.

More than 270 Hezbollah fighters and 50 civilians, including medics and journalists, have been killed in Israeli strikes on southern Lebanon. About a dozen Israeli troops and half as many civilians have been killed in northern Israel.