Hezbollah leader Hassan Nasrallah has rejected indictments of four of its members over the 2005 assassination of Lebanon's former PM, Rafiq Hariri.
He also said no power would be able to arrest the "honourable brothers", who have not yet been named officially.
It was Nasrallah's first reaction to the indictments issued by the Special Tribunal for Lebanon (STL) on Thursday.
The Shia Islamist movement has repeatedly denounced the UN-backed tribunal and vowed to retaliate.
Rafik Hariri and 22 others were killed in February 2005 in central Beirut when a huge bomb went off near his motorcade.
Hariri's son, Saad, welcomed the indictments and described them as a "historic moment" for Lebanon. 'Israeli plot'
In a televised speech on Saturday, Sayyed Nasrallah rejected "each and every void accusation" made by the STL, saying it was tantamount to an attack on the group.
He said the four group members were brothers "who have an honourable history in resisting Israeli occupation". Women pass by a giant portrait of former Lebanese Prime Minister Rafik Hariri near his grave, Beirut, Lebanon, 30 June 2011 Rafik Hariri is widely credited with getting Lebanon back on its feet after the 15-year civil war
Sayyed Nasrallah went on by describing The Hague-based tribunal as biased and part of an Israeli plot.
The Hezbollah also urged people to stop worrying about the potential for conflict, saying the tribunal's indictments would not lead to civil war in Lebanon.
On Thursday, Lebanon's state prosecutor, Saeed Mirza, said he had received the indictments and four arrest warrants from an STL delegation in Beirut.
The STL later confirmed the indictments, stating that the judge "is satisfied that there is prima facie evidence for this case to proceed to trial".
It added that it would not reveal the identities of those indicted.
However, Lebanese Interior Minister Marwan Sharbil has told the AFP news agency that the names of the men charged are Mustafa Badr al-Din, Salim al-Ayyash, Assad Sabra and Hassan Unaisi.
Mr Badr al-Din was jailed in Kuwait over a series of bombings in 1983, and is a brother-in-law of the late top Hezbollah military commander, Imad Mughniyeh, who was assassinated in a 2008 bombing in Damascus.
Leaks from the tribunal suggest it is mainly relying on mobile phone evidence to accuse the Hezbollah members, the BBC's Owen Bennett-Jones in Beirut reports.
The Lebanese government now has 30 days to arrest the four men, but Sayyed Nasrallah said they would not be detained not even in "300 years".
With Hezbollah being a strong force within the government, no-one is expecting the arrests, our correspondent adds.