Prime Minister Benjamin Netanyahu has said Israel is "acting" to prevent Syrian weapons reaching Lebanon's Hizballah and will continue to do so.
Netanyahu, speaking at the start of the weekly cabinet meeting on May 19, said the Middle East was going through its most sensitive period for decades, with the conflict in Syria at the center of the turmoil.
Netanyahu said Israel is "prepared for any scenario" to protect 'the security interests of the citizens of Israel in future."
His remarks came two weeks after Israel carried out air strikes near Damascus, which a senior Israeli source said were aimed at preventing the transfer of sophisticated Iranian weapons to Hizballah, the Lebanese Shi'ite ally of Syrian President Bashar al-Assad.
Netanyahu on May 14 held talks in Russia on the Syrian crisis.
Russia is Syria's main supplier of weapons.
Meanwhile, rights watchdog Syrian Observatory for Human Rights says Syrian troops backed by fighters from Lebanese militant group Hizballah have launched an attack on the rebel-held central town of Qusayr.
The London-based group said soldiers backed by tanks launched the May 19 assault after heavy bombardment by aircraft and artillery. At least 20 people were killed.
The group said Hizballah fighters "are playing a central role in the battle."
State television said that the army had "tightened the noose on the terrorists" in Qusayr.
Also on May 19, UN Secretary-General Ban Ki-moon said in Moscow that he hopes an international conference to negotiate a peaceful resolution to the conflict will be held early next month.
Washington and Moscow have agreed to try to bring Syria's regime and opposition to the negotiating table, but no date has been set.
Based on reporting by AFP and Reuters