Prime Minister Benjamin Netanyahu admitted Sunday that Israel has acted to prevent the transfer of weapons to the radical Shiite Hezbollah movement in Lebanon, dpa reported.
He added it would continue to do so, hinting at possible further pinpoint airstrikes on weapons shipments if necessary.
Netanyahu spoke two weeks after alleged Israeli airstrikes outside Damascus, targeting supplies of missiles earmarked for Hezbollah.
Israel has not confirmed or denied that it was behind the strikes.
The security of its citizens was Israel's top interest, Netanyahu told his cabinet, and his government was "acting in a responsible, determined and weighed manner" to secure that.
It was doing so "in accordance with the policy that we have set to prevent as much as possible the dripping (transfer) of advanced weapons to Hezbollah and other terrorist elements."
"We will act to secure the security interest of Israel's citizens also in the future," he added.
The Middle East was going through "one of the most sensitive times in decades," he said, especially because of the "escalating turmoil in Syria."
"We are closely following the developments and events there and we are prepared for any scenario," he said.
Netanyahu's remarks came as The Sunday Times reported that Syria had put its most advanced missiles on standby with orders to hit Tel Aviv if Israel launched another raid on its territory.
The London weekly said reconnaissance satellites had been monitoring the deployment of the Syrian Army's Tishreen surface-to-surface missiles.
Netanyahu's remarks also came after a senior Israeli official sent a message to President Bashar al-Assad via The New York Times.
The official contacted The New York Times last week, told the newspaper that Israel was "determined to continue to prevent the transfer of advanced weapons to Hezbollah," and warned that if Assad reacted by attacking Israel, or tried to attack "through his terrorist proxies," he would risk "forfeiting his regime" because Israel would retaliate.
Israel Radio reported Sunday that Israel decided to send the public message to Assad via The New York Times, after reassuring and calming messages sent to him via third parties "did not register."
According to the radio report, US officials apologized for a leak by Pentagon officials who had confirmed on condition of anonymity to US media that Israel was behind the airstrikes in Syria.
The off-the-record confirmation had forced Assad to react more sharply than he would have otherwise, threatening an escalation of the situation, the report said.
The leak was initiated by lower ranking Pentagon officials and the issue was thoroughly being investigated, the radio quoted US officials as saying in their apology to Israel.