The raids and missile strikes have targeted regime forces and their depots as well as fighters from President Bashar al-Assad's Iranian backers and his allies in Lebanese Hezbollah.

Israeli Prime Minister Benjamin Netanyahu has vowed not to let Iran entrench itself in Syria.

Here is a recap of some of the major reported raids, which Israel does not always confirm.

- First strikes -

In January 2013 Israeli planes hit a military complex near Damascus suspected of holding chemical agents, according to a US official.

Israel later implicitly confirms the strike for the first time since the start of the Syrian war in 2011.

In May 2013 Israel strikes the Jamraya scientific research centre near Damascus, a weapons depot and an aircraft unit.

The Syrian Observatory for Human Rights, a Britain-based war monitor which relies on a network of sources inside the country, says 42 soldiers are killed.

- Hezbollah hit -

In January 2015 a raid on the Syrian side of the Golan Heights kills six Hezbollah personnel and a general from Iran's Islamic Revolutionary Guard Corps.

Hezbollah commander Samir Kantar, who spent almost 30 years in Israeli prisons, dies in a raid blamed on Israel near Damascus in December 2015.

In March 2017 Israel says it has targeted "sophisticated" weapons destined for Hezbollah near the central town of Palmyra.

In December 2017 Israeli planes again target the Jamraya research centre along with a weapons depot, according to the Observatory.

- Iranians targeted -

In February 2018 Israeli raids hit Syrian and Iranian targets after an Israeli fighter jet is shot down.

In April Syria and its ally Russia accuse Israel of a dawn bombing raid on a Syrian airbase that kills 14, including seven Iranians.

Later that month, at least 26 mostly Iranian fighters are killed in a raid Syria says bore the hallmarks of an Israeli operation.

In May 2018 an attack near Damascus, blamed on Israel, kills 15 pro-regime foreign fighters including eight Iranians.

Israel carries out dozens more raids that month on what it says are Iranian targets, as Iranian rocket fire hits the occupied Golan Heights.

At least 27 pro-regime fighters are killed, including 11 Iranians, the Observatory says.

- Russian plane downed -

In July Syria accuses Israel of bombing a military position in Aleppo province. At least nine pro-regime fighters die, including three foreigners.

Two months later Syrian air defences responding to an alleged Israeli strike accidentally down a Russian transport aircraft with a crew of 15, sparking tensions between Israel and Moscow.

At the end of 2018 Israel again bombs weapons depots near Damascus.

- Israel 'determined' -

On January 12, 2019 Syrian air defences shoot down Israeli missiles targeting a warehouse at Damascus airport, with Netanyahu saying Israel is "more determined than ever to act against Iran in Syria."

Three days later he tells Iran to remove its forces from Syria "fast" or face continued attacks.

The following week Israel says its Iron Dome air defence system has intercepted a rocket fired from Syria by the Iranian Revolutionary Guards' Quds Force.

In response, Israeli jets carry out further strikes inside Syria, with at least 11 fighters killed.

- Deadliest operation -

In the deadliest strikes since the start of the raids, Israel kills 57 regime forces and allied fighters in raids on eastern Syria overnight Tuesday.