Israeli and Syrian forces exchanged fire across the cease-fire line in the Golan Heights yesterday, amid rising US and Israeli threats of intervention in the US-led sectarian proxy war in Syria, which is rapidly spreading throughout the region.

Fighting in the Golan Heights started overnight when Syrian forces fired at an Israeli vehicle that allegedly crossed into Syrian territory. Israeli forces fired rockets into Syrian territory and claimed to have destroyed the source of Syrian fire.

The border fighting came only two days after Israeli Prime Minister Benjamin Netanyahu threatened to act “with determination” to prevent the transfer of arms from Syria to the Lebanese Shiite militia Hezbollah. Hezbollah has now intervened in the Syrian war to support the regime of President Bashar al-Assad against the US-backed Sunni Islamist opposition.

Netanyahu’s statement was widely interpreted as an Israeli threat to mount further unprovoked air strikes on Syria.

Since Obama’s reelection last November and twice this month, Israeli forces have bombed targets in Syria. This month’s bombings, hitting Syrian army targets in the capital, Damascus, were timed to coincide with an offensive by the Sunni opposition on the city. This offensive has been thrown back and forced into retreat, however, due, in part, to the intervention of Hezbollah forces in areas of southern Syria adjacent to Lebanon.

The reversals suffered by the opposition point to the minimal support it has in the Syrian population.

There are now intensifying threats of war coming from Israel as well as calls in Washington and in European capitals for stepping up the flow of arms to opposition forces or directly intervening with air strikes or a ground invasion. Speaking yesterday at the University of Haifa, Israel Defense Forces head Lt. General Benny Gantz said: “We will not allow the Golan to become a comfortable space for Assad to operate from. If he escalates the situation on the Golan Heights, he will have to bear the consequences.”

He implied that war could break out at any time, noting that “a day doesn’t go by” without the risk of a “sudden uncontrollable deterioration.”

In Washington, senators Robert Menendez (Democrat of New Jersey) and Bob Corker (Republican of Tennessee) have submitted a bill titled “Syrian Transition Support Act.” It would authorize the Obama administration to “provide defense articles, defense services, and military training” to Syrian opposition forces.

The bill bluntly spells out broader strategic calculations underlying the proxy war in Syria. It notes, “A change of government in Syria could be a significant blow to the Government of Iran and Hizballah [Hezbollah], which would lose a strong ally.”

That is, the Syrian war is in line with US imperialism’s strategic interests: isolating Hezbollah, the main threat to Israeli military hegemony in the Near East, and Iran, the main obstacle to US hegemony in the entire Middle East and to US control of the region’s oil.

In its presentation of the war, the bill advances lies and evasions similar to those with which pseudo-left forces such as the International Socialist Organization in the US, France’s New Anti-capitalist Party and Germany’s Left Party have promoted the US-backed opposition. It proposes to support opposition forces that are “protecting human rights” and “protecting the Syrian population against sectarian violence and reprisals.”

In fact, Sunni opposition militias armed under CIA supervision with funds from Washington’s Middle East allies are waging a bloody sectarian war with terror bombings and massacres. This was even recognized partially by Washington, which declared one of the main opposition forces, the Al Nusra Front, a terrorist organization responsible for nearly 600 terror bombings in the period up to December 2012.

On Monday, a spokesman for the US-backed Free Syrian Army (FSA) threatened a sectarian genocide of Shia Muslims—including the Alawite minority from which Assad’s family is drawn—in territory still held by the opposition, as it retreats in southern Syria.

He threatened that Shia communities would be “wiped off the map,” adding: “It’s going to be an open, sectarian, bloody war to the end.”

This comes a week after an opposition commander of the so-called “moderate” Farouq Brigade filmed himself desecrating the corpse of a Syrian soldier, cutting out his organs and biting into one of them. He also called for the killing of Alawites.

Washington, its allies, and its Sunni Islamist proxies fear, in particular, the loss of the town of Qusayr. This would cut supply lines connecting opposition fighters around Homs from the majority-Sunni port of Tripoli, in Lebanon, from which they receive weapons supplies. It would also open direct land routes connecting the Assad regime in Damascus to the Alawite heartland on Syria’s Mediterranean coast.

According to AFP, Hezbollah sources confirmed that they had sent “new elite troops to Qusayr.” The Syrian state daily Al Watan reported yesterday that Syrian regime forces had retaken Qusayr’s official buildings and “raised the Syrian flag” over them.

Washington has denounced Hezbollah’s intervention, with US President Barack Obama calling Lebanese President Michel Sleiman to criticize Hezbollah’s “active and growing role” in Syria. The US State Department said Hezbollah’s actions “exacerbate and inflame regional sectarian tensions and perpetuate the [Syrian] regime’s campaign of terror.”

In fact, it is Washington and its allies that are backing forces advocating and carrying out sectarian massacres and terror attacks. By giving Turkey and the Persian Gulf monarchies carte blanche for an international campaign to arm rabid Sunni sectarian forces, overseen by the CIA, they are spreading sectarian bloodshed across the entire region.

Fighting continued in Iraq yesterday, with 19 people killed and one hundred wounded in bombings, as the sectarian tensions unleashed by US support for Sunni Islamist militias in Syria spilled over into Sunni fighting against the Shia-led Iraqi regime. Opposition Free Syrian Army (FSA) fighters also fired into Lebanon yesterday, targeting Hezbollah positions with Grad rockets from the Qusayr area in Syria. According to Iran’s Press TV, they targeted the villages of Hawsh al-Sayyed Ali and al-Qasr. The rockets targeting al-Qasr exploded close to the Zainul Abideen orphanage but caused no casualties, according to the orphanage’s director, Mohammad al-Saeed.