Thousands of supporters of the Shiite Hezbollah movement protested on Wednesday in the southern city of Tyre against a US-made film mocking Islam and cartoons of Prophet Mohammed, hours after gunmen fired at a KFC restaurant.
"America, America, you are the great satan!" and "Israel is the enemy of the Muslims!" chanted protesters as they poured onto the streets of Tyre.
Protesters carried posters saying: "We sacrifice ourselves for you, O messenger of God," "All our problems are from America," and "Muslims and Christians in defence of the prophet's dignity."
Wednesday's protest came after Hezbollah leader Hassan Nasrallah on Monday called for such demonstrations across Lebanon following the spread of the anti-Islam film on Internet, saying it was "the worst attack ever on Islam."
Most demonstrators travelled to Tyre from nearby villages in south Lebanon, much of which was destroyed by a deadly war with Israel in 2006.
Support for Hezbollah in this war-battered region is near-total, with majority of its residents Shiite.
Wednesday's protest were being held against the film, "Innocence of Muslims," and after a French weekly published cartoons of a naked Prophet Mohammed.
The movie triggered violent protests across the Muslim world, with 30 people killed in the unrest over the past week, including one who died in clashes with the security forces in Lebanon.
Addressing the crowd in Tyre, Hezbollah executive bureau member Nabil Qaouq warned the US and France against entering into a confrontation with the Muslim world.
"O Americans, it is better for you to take a step back, and not to get stuck in an all-out confrontation with the Islamic ummah (nation)," said Qaouq.
"France has also chosen to take a position of animosity against the ummah," he said. Both countries should "be aware of the Muslim ummah's rage, because it is capable of doing anything to defend the dignity of the messenger of God."
"I am ready to sacrifice my blood, my daughter and my money for the prophet," protester Mohammed Hallawi told AFP, adding he would like to see non-Shiites join the protests too."
Lebanon's Sunni Muslim cleric Ahmed al-Assir has called for a demonstration in downtown Beirut on Friday to protest what he described as "attacks on Muslims."
Hours before demonstrators flooded the streets of Tyre, gunmen opened fire on a KFC fast-food restaurant, just days after another one was torched, a security official said.
The attack occurred at dawn in the southern city of Nabatiyeh. The US chain's restaurant was not open at the time and no one was reported hurt.
On Monday, the United States updated its travel warning for Lebanon and suspended grants to Americans wishing to study in the country.
And on Wednesday the French embassy sent a mobile phone text message to citizens in Lebanon, urging them to be cautious.
"Be careful of your movements and stay away from large gatherings" and buildings that might be the site of protests, especially on Friday, the embassy said.
The Lebanese army has also stepped up security measures to protect the French ambassador's residence in Beirut, while an AFP correspondent in the southern city of Sidon said an army unit was deployed around the French cultural centre and armed guards posted at the gates.