Syria today claimed to have destroyed an Israeli vehicle that crossed the ceasefire line in the Golan Heights.

The Israeli military chief of staff, Benny Gantz, warned that Israel risked being drawn into a “security deterioration in our region at any moment, a deterioration which could rapidly spin out of control”.

It said troops destroyed the vehicle “with those in it” and warned that any attempt to infiltrate its sovereignty would face “immediate and firm  retaliation”.

The Israeli army said one of its vehicles was damaged, but reported no injuries and said it “returned precise fire”. It also reported no injuries from two earlier incidents near Tel Hazeka, also in the Golan Heights, and said it did not return fire in either case.

Cross-border fire from Syria’s two-year conflict has increased in recent months. As Israel expressed “concern”, fears grew that the increasing role of Lebanese militant group Hezbollah, loyal to Syrian president Bashar al-Assad, could cause the war to spill over Syria’s borders.

Israeli prime minister Benjamin Netanyahu said his country is prepared to launch further raids against Syria if it believes the war threatens its borders. Israel and Hezbollah fought a six-week war in 2006.

Hezbollah guerrillas were reported this week by activists to have supported Syrian forces in a major offensive in the rebel-held town of Qusair, six miles from the Lebanese border, in which at least 32 people were killed.

Mr Netanyahu said Israel is “preparing for every scenario. We will act to ensure the security interest of Israel’s citizens in the future”. Israel has neither denied nor confirmed reports it attacked sites near Damascus this month where it believed Iranian-supplied missiles awaited delivery to Hezbollah.

Meanwhile, Syrian TV showed film of what it said was an Israeli military vehicle used by anti-Assad fighters. Israel said the Jeep was decommissioned a decade ago, and dismissed the footage as “poor propaganda”.

Foreign Secretary William Hague said the UK is stepping up efforts to find a political solution in Syria. Opposition groups meeting in Spain today said they oppose all negotiation with Assad’s government unless it is aimed at him giving up power

the cross-border exchange of fire in the Golan Heights between the Israeli and Syrian armies early on Tuesday triggered a claim by the Damascus regime that a jeep manned by Israeli troops had entered Syrian territory and was destroyed.

The Israeli Defence Forces (IDF) denied the claim, saying shots were deliberately fired at a patrol inside the Israeli-controlled the Golan Heights, causing minor damage and no injuries. “In response, IDF forces returned precise fire at the source and reported a direct hit,” it said.

It was the latest in a string of cross-border incidents in recent months, which have raised concerns that the two-year-old civil war in Syria could spill over into the neighbouring Golan Heights, which Israel has occupied for more than 40 years.

Israel has also launched air strikes on weapons targets inside Syria three times since the start of the year, intensifying fears that the civil war could develop a regional dimension.

A statement from the Syrian army, published on the official Syrian Arab News Agency (Sana) about six hours after the shooting incident, said it had “destroyed an Israeli vehicle with everyone in it” that entered Syria.

It was the third time in four days that shots fired in Syria have crossed into the Israeli-occupied Golan, close to Israeli army outposts or patrols, according Israeli reports. There have been a further three occasions this month when mortar shells have landed in the Golan.

Until now, the IDF has maintained that such cross-border incidents are accidental, rather than aimed at its forces. However, Israel Radio quoted officials as saying that this week’s gunfire was deliberately targeted at patrolling IDF troops.