Hezbollah Secretary-General Hassan Nasrallah made a brief appearance Tuesday in Beirut during a procession marking the Shiite holy day of Ashura.
Nasrallah rarely appears in public out of assassination fears. He appeared briefly in public before making a broader statement via video link.
"This resistance and its weapons will continue to exist and your conspiracies as well as your psychological, political and intelligence wars will not destroy us," he was quoted by Lebanon's Daily Star newspaper as saying.
Nasrallah, who enjoys support from the Baathist regime in Syria, warned supporters to be wary of conspiracies plotted by the United States and Israel.
The real threat, he said, comes from the West, which aims to destroy Syria.
Syria is facing increasing isolation by the international community for its crackdown on opponents to Syrian President Bashar Assad. Nasrallah said he stood by his longtime ally but supported reforms in the country.
"There are some who want to make up for their defeat in Iraq and their inevitable loss in any change in the situation in Syria for the benefit of Israel," he added.