An Israeli soldier takes position near the border with Syria in the Israeli controlled Golan Heights. (Ariel Schalit/AP)

Israeli forces were on heightened alert on Monday along their country’s northern border with Syria after the military reported thwarting a militant attack with airstrikes.

Details about the late Sunday incident were not clear, but unrest from Syria’s civil war has occasionally spilled over into the heavily guarded border zone near the Israeli-held Golan Heights.

Arab news media have run stories on airstrikes allegedly carried out by Israel in the past few days against the Hezbollah militia, an Iran proxy, and Syrian army targets.

A statement from the Israeli army on Sunday said its forces had come across “a group of armed terrorists who had approached the border with an explosive device intended to be detonated against [Israeli] soldiers.”

Israel said its aircraft responded with strikes, but it did not confirm casualties or identify the group that allegedly attempted the border attack. Israeli media said four men were killed.

Israeli media reported Monday night that two of the four men were the sons of a former political prisoner from the Druze village of Magdal Shams, on Israel’s side of the Golan Heights. The family left Israel for Syria in the 1980s. There was no official confirmation of their identities, however.

Amos Gilad, director of the political security staff at the Defense Ministry, told state radio that it was too early to determine who was behind Sunday’s infiltration attempt but that “Israel’s response is usually strong and sharp, strengthening its deterrence.”

Israeli Prime Minister Benjamin Netanyahu wrote in a Twitter post, “Any attempt to hurt our soldiers or civilians will be met with a firm response, such as the [military] operation tonight that foiled an attempted terror attack.”

On Saturday, Arab media reported that Israeli airstrikes hit Hezbollah and Syrian army sites north of Damascus, the Syrian capital. Reports said the targets were Syrian army divisions thought to be in possession of strategic weapons and long-range missiles. The Israeli military did not respond to the claims.

On Monday morning, after the border incident, Arab media again reported an airstrike in the same area — near Syria’s Qalamoun mountains — aimed at Syrian army and Hezbollah weapons stocks. Israel denied Monday’s reports, attributing any such attack to the civil war in Syria between the government of President Bashar al-Assad and rebel factions.

“There is a question mark over all these incidents, but, on the surface, it does seem to follow a pattern that we have become used to over the past two years — with Israel using its air power to prevent the transfer of weapons to Hezbollah,” Jonathan Spyer, director of the Rubin Center, a think tank at Israel’s Interdisciplinary Center Herzliya, said in an interview.

Although Israel has officially denied any connection to the airstrikes in Syria, Defense Minister Moshe Yaalon told a forum in Tel Aviv on Sunday night that Israel “would not allow quality arms to be transferred to Hezbollah.”

He accused Iran, which backs the Assad regime, and Hezbollah of trying to establish “a terrorist infrastructure along our border with Syria.”

During the four years of civil war in Syria, there have been at least eight unconfirmed reports of Israeli airstrikes on Hezbollah weapons consignments. Hezbollah has been heavily involved in the fighting in Syria, supporting Assad’s regime.

In January, tensions between Israel and Hezbollah ratcheted up after Israeli helicopters fired missiles at the group’s vehicles traveling in a Syrian-controlled portion of the Golan Heights. Six Hezbollah fighters were killed, as well as a senior Iranian military commander.

Israel and Hezbollah fought a three-week war in summer 2006. Recent Israeli military assessments suggest that Hezbollah still poses the biggest threat to Israel’s security.

Read more:

CIA and Mossad killed senior Hezbollah figure in car bombing

Deadly border clashes stoke fears of war in Israel, Lebanon

Israel worries as al-Qaeda affiliates gain control of Syrian side of Golan frontier

Israeli military maps Hezbollah bunkers