BEIRUT, Lebanon – Reports that a U.N. tribunal will blame the 2005 assassination of former Lebanese Prime Minister Rafik Hariri on the Shiite Muslim militia Hezbollah has triggered fears of violence in this small, unstable country.

Hezbollah chief Hassan Nasrallah said late Thursday that Saad Hariri, the current prime minister and son of the slain Sunni politician, had told him that the U.N. investigators examining the assassination would pin responsibility on “undisciplined members” of Hezbollah.

Nasrallah said the group, which is backed by Iran and Syria, “categorically” rejected the accusations as a Western and Israeli conspiracy.

“There is now a new scheme targeting the resistance,” he said, referring to Hezbollah’s armed opposition to Israel, this time “targeting it directly, through the tribunal, and through exploiting a just and emotional case that all Lebanese agree on.”

Many Lebanese fear that any effort to blame Hezbollah for the killing could spark street clashes between Shiites and Sunnis or even bring about a repeat of a brief May 2008 conflict that Hezbollah supporters have repeatedly referred to in speeches over the last week.

“The main Lebanese actors don’t want to make anything of this because they know it will blow up in their face,” said Paul Salem, a Middle East analyst at the Carnegie Endowment for International Peace. “They know if they make any move, there will be another May 2008.”

The assassination of Hariri, who also was Lebanon’s richest man as well as a conduit for Saudi Arabian influence in the country, set the stage for the forced Syrian withdrawal from Lebanon and the emergence of a Western-backed political bloc of Sunnis, Christians and Druze opposed to Hezbollah.

After the May 2008 conflict, the country’s main players reached a power-sharing agreement that let the militia keep its arms and private telecommunications network. The tentative and relatively peaceful status quo has led to a flowering of commercial and civic life that analysts say could be squelched by the tribunal’s ruling.

The office of Daniel Bellemare, the Canadian prosecutor heading the U.N. probe, has been tightlipped about the case.