A Syrian flag flutters in Damascus, Syria April 20, 2018. REUTERS/Ali Hashisho

Syria’s army said on Monday the country’s air defenses had intercepted “Israeli aggression” over the capital, Damascus, in the latest stepped-up bombing of Iranian targets inside the country over the last two months.

The Israeli military, which just began a surprise air force combat drill along the country’s northern border, said “it did not comment on foreign reports,” according to a spokeswoman.

Syrian state media did not give details of what was hit by the Israeli air force. Israeli military planes flew over the Golan Heights to hit targets on the edge of the capital, an army statement said, without mentioning casualties but adding air defenses downed most of the missiles.

“Our air defenses are continuing to repel the Israeli missile attacks over the skies of the capital,” the Syrian army said in a statement.

A Syrian military defector said the bombing raids hit a major army division in the town of Kiswa, almost 14 km (8.7 miles) south of the capital, in a sprawling area where Iranian-backed militias have a dominant presence.

Witnesses heard large explosions on the southern edge of Damascus, an area where Iranian-backed militias are entrenched, residents said.

Israeli officials have acknowledged carrying out attacks inside Syria aimed at ending Tehran’s entrenched military presence in Syria.

Military chief of staff Aviv Kochavi said at the end of last year that Israeli missile strikes had “slowed down Iran’s entrenchment in Syria,” hitting more than 500 targets in 2020.

The army said on Monday that during the surprise drill, which will last until Wednesday, there would be an increase of air traffic throughout the country and that explosions could be heard in northern Israel.

It said the “exercise simulates combat scenarios in the northern front, and will test all components in the (air force’s) core missions, including maintaining aerial superiority, protecting the country’s skies, as well as attacking and gathering intelligence.”

Western intelligence sources say Iran’s military influence has expanded in Syria in recent years, prompting Israel to escalate its campaign to prevent its arch rival from establishing a major military foothold along its border.

Iran’s proxy militias, led by Lebanon’s Hezbollah, now hold sway over vast areas in eastern, southern and northwestern Syria, as well as several suburbs around Damascus. They also control Lebanese-Syrian border areas.

Israel, which in the last two months staged some of its biggest strikes yet inside Syria, has concentrated on Al Bukamal, the Syrian city that controls the border checkpoint on the main Baghdad-Damascus highway.

The widening military campaign was part of a so-called “campaign within wars”, which, according to Israeli generals and regional intelligence sources, have been tacitly approved by the United States.

The operations that aim to prevent Tehran from changing the balance of power in Syria in its favor have gradually eroded Iran’s extensive military power without triggering a major increase in hostilities, regional intelligence sources say.