Hezbollah leader Hassan Nasrallah called on regional states to join the fight against the Islamic State group on Sunday, saying "they are not stronger than Israel and the United States, and the nations of the region have already defeated Israel and the United States."
He explained that "one of the reasons for the Israeli position of power over the years is the partition plan the region has adopted," and noted that the danger the Islamic State poses was no lesser than that posed by Israel.
Nasrallah dismissed the US-led coalition fighting against IS, saying the jihadists continued to move freely despite its air strikes, and mocked the coalition's efforts, saying "the number of attacks the international coalition conducted in a few months is less than what Israel did in far less time in Lebanon and Gaza."
Nasrallah's speech was broadcast to thousands of supporters on large screens at an event in Nabatieh marking 15 years since the IDF withdrawal from southern Lebanon. The event was attended by senior Hezbollah officials and other prominent Lebanese figures closely linked to the organization, including Lebanon's Parliament Speaker, Nabih Berri, and Syria and Iran's ambassadors to Lebanon.
The Hezbollah leader said that those who remain silent to ISIS's atrocities will be their first victim in the future.
"Daesh's first victim in Lebanon will be the Al-Mustaqbal faction," Nasrallah said of the Sunni anti-Hezbollah faction in Lebanon, using the Islamic State's Arabic-language acronym.
He stressed that sitting and waiting for the Islamic State to attack was not an option, "we must take the initiative and look for options to fight these armed organizations. Today we are facing a kind of danger that is unprecedented in history, which targets humanity itself," he said.
"This is not a threat to the resistance in Lebanon on to one sect or to the regime in Syria or the government in Iraq or a group in Yemen," he added.
"This is a danger to everyone. No one should bury their heads in the sand.
"We invite everyone in Lebanon and the region to take responsibility and confront this danger and end their silence and hesitation and neutrality."
In a message to Israel, the Hezbollah leader vowed that despite the fighting in the region, "we will stay in southern Lebanon."
While his organization was concentrating on the fight against rebels trying to topple Syrian President Bashar Assad and against the Islamic State, "we did not evacuate this front (southern Lebanon) and we will not evacuate it. We must be on two fronts. We continue operating on the front against Israel - other issues do not distract us."
He went on to say that Israel must know that "the resistance is at the height of its readiness," noting that "the enemy knows this better than the Lebanese people. That is why it fears the resistance and continues its psychological warfare."
"We are very alert and there is no possibility that we would look away even for a moment from the Israeli enemy," he concluded.
He also acknowledged for the first time that Hezbollah was fighting throughout all of Syria, and not just in areas near the border with Lebanon.
"We are fighting alongside our Syrian brothers, alongside the army and the people and the popular resistance in Damascus and Aleppo and Deir Ezzor and Qusayr and Hasakeh and Idlib," he said.
"We are present today in many places and we will be present in all the places in Syria that this battle requires."
Nasrallah also said that an offensive his group is leading in the mountainous region of Qalamoun along the border between Syria and Lebanon will last "until the borders are secured."
He said the residents of the area "will not accept the presence of terrorists and takfiris in any of the Bekaa or Arsal outskirts." Takfiri is a term for a hardline Sunni Muslim who sees other Muslims as infidels, often as a justification for fighting them.
Lebanon suffered its own civil war from 1975 to 1990, and officials there have warned Hezbollah against launching a cross-border attack which they say would drag the country further into the Syrian conflict.
Some also fear Hezbollah's offensive might provoke Sunnis in Arsal, a Lebanese town whose people have sympathised with the revolt against Assad and have welcomed thousands of Syrian refugees in the past four years.
Nasrallah told off those in Lebanon who were criticizing Hezbollah for their high number of casualties in Syria: "They should be ashamed of themselves because thanks to these casualties, they live in security and peace. We're not ashamed of our casualties."
Reuters and AFP contributed to this report.