Hassan Nasrallah, the leader of Hezbollah, has tried to implicate Israel in the murder of Rafiq al-Hariri, the former Lebanese prime minister.
In a video address to journalists from an undisclosed location on Monday, Nasrallah said he had evidence to prove Israel's complicity in al-Hariri's assassination in Beirut, the Lebanese capital.
"He has not provided undisputed, solid proof that implicates Israel," Al Jazeera's Rula Amin reporting from Beirut said.
The Hezbollah leader, however, said that "there is enough evidence pointing to Israel," our correspondent said.
Al-Hariri and 22 others were killed on the Beirut seafront on February 14, 2005.
The assassination sparked an international outcry and led to the withdrawal of Syrian troops from Lebanon.
The murder has been widely blamed on Syria, but Damascus has routinely denied involvement.
Fawaz Gerges, a Middle East analyst, told Al Jazeera that Nasrallah "talked about who has the most to benefit from the assassination ... [by trying to] provide a very complex case by drawing a historical link between Israel" and the killing.
Nasrallah said Israel used spying and covert operations to attempt to drive a wedge between Hezbollah and the Lebanese government.
Among the material presented was what he described as Israeli reconaissance footage intercepted by Hezbollah of areas frequented by al-Hariri.
Israel denied the "ridiculous" accusations.
"Everyone in the world knows, even the Lebanese, that Nasrallah's accusations are ridiculous," AFP news agency quotes a senior Israeli official as saying.
It was clear that the allegations were "coming from the pressure on [Nasrallah] over the international community's suspicions about Hezbollah's involvement in Hariri's murder," the unnamed official said.
Aaron Klein, a political commentator in Jerusalem, told Al Jazeera that the contents of Nasrallah's rare speech were not surprising.
"This is exactly what everybody in Israel was expecting, which was to use the Jewish state as a scapegoat because he is up against a rock and a hard place," Klein said.
A UN court probing the assassination of al-Haririis planning to charge Hezbollah members in the killing, Nasrallah said in July.
Nasrallah criticised the UN investigation because it "does not look into the possibility that Israel is implicated, we believe it is biased".
Our correspondent said that Hezbollah considers the tribunal "an Israeli project to create strife in Lebanon".
Impending charges from the international body had pushed Lebanon into a "very sensitive phase", Klein said.
Hezbollah fought a devestating war with Israel in 2006.
Klein said that a UN verdict against Hezbollah would be "devastating for them in terms of the internal politics" as it could spark anger among other sectors of Lebanese society.
Rula Amin said that "Hezbollah is trying to dismiss the findings of international investigations. They want to discredit the basic information that investigators had depended on in making their conclusions".
"He is trying to say that the findings are not credible and politically motivated ... he is trying to do is build a case in which he says Israel is a legitimate suspect," our correspondent said.