Israel is concerned about Iranian plans to intensify its military operations with Hizbollah in southern Syria, close to the Golan Heights border.

The Israeli view is that the military push is at least partly a result of Iranian fears that Saudi Arabia and other Sunni nations are preparing to beef up their support for the rebels in Syria.

The civil war in Syria has been raging for over four years and despite a number of skirmishes near the border with Israel, the main fighting has largely been in other parts of the country.

In January, an Israeli drone strike near the border killed a number of senior Iranian officers and Hizbollah commanders including Jihad Mughniyeh and Revolutionary Guards general Muhammad Ali Allahdadi. The hit was widely seen as a warning from Israel that it was aware of the Iranian plans to establish a presence on the Golan.

Since then, Hizbollah and Syrian forces loyal to President Bashar Assad have deployed thousands of fighters around the Golan, with the stated intention of securing the southern approaches to Damascus. General Qassem Soleimani, commander of Iran's Al-Quds force, has also visited the area.

"The Iranians are worried about the determination of the Saudis to counter their influence in the region" said a senior IDF officer. "They are seeing now a pincer move from the south in Yemen and in the north in Syria designed to cut through their Shia axis. Their presence now on the Golan is partly an attempt to create pressure on Israel and to respond to the Saudi plans."

While most of the attention this week was on the Saudi offensive in Yemen, under the radar, the Saudis and their partners have been stepping up support for Sunni rebels in Syria, including Jubhat al-Nusra. The Islamist group has been making gains both in northern Syria, capturing Idlib, and areas close to the Israeli border in the south.

All sides have been bolstering their forces in the region. Last year, Israel created a new division to provide security on the Golan, and Hizbollah formed - with Iranian support - a new unit made up of Lebanese, Syrian and Palestinian fighters. The battle group is currently struggling to dislodge the rebels from the town of Daraa, near the Israeli border.

While Israel has not confirmed that it is assisting the Syrian rebels beyond treating wounded fighters, the Netanyahu government's policy on Syria has undergone a drastic change.

Two years ago, Mr Netanyahu was warning Western nations of supplying arms to the rebels, out of the concern that they could fall into the hands of Al Qaida. With the increased involvement of Iran and the closer secret ties with the Saudi-led coalition, Israel is more focused on limiting Hizbollah and Iran's operations close to its border.