Hizbullah leader Sheikh Hassan Nasrallah promised thousands of supporters that it would eventually bring down Lebanon's Western-backed government.
It was the seventh day of street demonstrations by Hizbullah and other pro-Syrian parties aimed at pressuring Prime Minister Fuad Saniora to quit in a deepening political crisis.
The prime minister has vowed to stand firm against protesters.
In a speech delivered yesterday on huge screens in two central Beirut squares, Mr Nasrallah accused Mr Saniora of conniving with Israel during its month-long war with Hizbullah during the summer.
He claimed Mr Saniora ordered the Lebanese army to confiscate Hizbullah's supplies of weapons - his sharpest attack on the prime minister since the August ceasefire that ended the fighting.
He added that government officials had asked US envoys to persuade Israel to destroy Hizbullah. "Those are the ones responsible for the war, not the resistance," Mr Nasrallah said.
Hizbullah has gained increasing political clout after the war, which began after Hizbullah guerrillas snatched two Israeli soldiers patrolling the southern Lebanon border.
It wants to topple Mr Saniora's government because it has rejected demands for forming a national unity government that would give the pro-Hizbullah factions veto power in the Cabinet.
But Mr Saniora's allies have accused Hizbullah of being influenced by Iran and Syria, which they claim want to destabilise Lebanon by supporting the militant group's plans to oust the government.
Mr Nasrallah said protests would continue until Hizbullah's demands are met.
AP