Israeli jets struck a mountainous area near the Lebanese-Syrian border late Monday, hitting a transit point in the war between forces loyal to Bashar al-Assad’s regime in Damascus and the mostly Sunni rebels fighting to bring him down.

According to Lebanon’s National News Agency and other Lebanese media, Israeli aircraft launched two raids near the villages of Nabi Chit and Janta, a stronghold of Hizbollah, the Shia militia. The area includes smuggling routes straddling the border with Syria and is adjacent to some of the most heavily contested districts around the Syrian capital, Damascus.

Hizbollah, a powerful militia, political organisation and social services provider rooted in Lebanon’s Shia community, has provided military support to the Assad clan as it attempts to fend off a popular uprising against his family’s four-decade rule.

The target of the attack remained unclear. Lebanon’s Daily Star quoted a Lebanese security official as saying Israel launched four rockets against a shipment of “qualitative” weapons being transported across the border. The Syrian Observatory for Human Rights said the target was a Hizbollah “missile base”.

In its official media, Hizbollah denied the raids hit anything significant. But witnesses told Arab media they heard jets flying at unusually low altitudes and extraordinarily powerful blasts late Monday. NNA reported an increase of Israeli flights over Lebanese airspace, including four aircraft that flew across the Bekaa Valley and away through south Lebanon.

Israel launched at least a half dozen air strikes along the Syria-Lebanon border last year, according to foreign officials.

The Israel Defence Forces, in keeping with the country’s policy of not commenting about its involvement in tactical attacks on its neighbours, did not confirm or deny its involvement in the strikes. ‘We don’t refer to foreign reports,’ the IDF said.

Israel has warned repeatedly that it would not tolerate the transfer of what it calls game-changing weapons to Mr Assad’s government or from Syria to Hizbollah, its ally based in southern Lebanon.

Hizbollah, a staunch ally of the Iranian regime, has long been believed to use border crossings and smuggling routes under its control to bring powerful weapons into Lebanon to be used in any future war against Israel. Since the uprising began against the Syrian regime in 2011, Hizbollah has been moving personnel and at least some of its weaponry into Syria to help fight the rebellion.

At a joint press conference with German leader Angela Merkel in Jerusalem on Tuesday, Benjamin Netanyahu, prime minister, when asked whether Israeli air force jets were behind the strike, said, in remarks quoted by the Jerusalem Post: “Our policy is clear – we will not speak about reports of what we did or didn’t do – but we do all that is necessary in order to defend our citizens.”

Although Hizbollah has been weakened by its involvement in Syria’s civil war, Israel still considers the guerrilla movement one of its most formidable regional enemies. Military experts estimate the group has 100,000 missiles and rockets in its arsenal.

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