Israel conducted a rare airstrike inside Syria near the border with Lebanon, hitting a convoy of trucks, foreign officials said yesterday, amid fears that President Bashar al-Assad’s regime is providing weapons to the Islamic militant group Hezbollah.

Regional security officials said Israel had been planning in the days leading up to the airstrike to hit a shipment of weapons bound for Hezbollah, Lebanon’s most powerful military force. Among Israeli officials’ chief fears is that Assad will pass chemical weapons or sophisticated anti-aircraft missiles to Hezbollah — something that could change the balance of power in the region and greatly hinder Israel’s ability to conduct air sorties in Lebanon.