An international tribunal was established under United Nations auspices, and many Lebanese believed that an indictment of top Syrian officials — widely believed to be the culprits — could help protect Lebanon’s sovereignty.

But in recent weeks, a consensus has emerged in Lebanon — presumably, through leaks — that the tribunal will soon indict members of Hezbollah, the militant Shiite movement, for playing a role in the killing. That accusation, which has been rumored since last year, is already raising tensions in Lebanon, and some fear it could provoke another bloody internal conflict between Hezbollah and its pro-Western rivals like the one that took place in May 2008.

Hezbollah, which is allied with Syria, remains the most powerful political and military force in Lebanon, and its leader, Hassan Nasrallah, has made clear that he will not accept any indictment of Hezbollah members. He has warned the Lebanese authorities to do the same. (The tribunal, which is based in the Netherlands, has not issued any statements about potential indictments.)

In a July 16 speech, Mr. Nasrallah cast the tribunal as part of an Israeli plot. That provoked angry responses from some of Lebanon’s Western-aligned political figures, who said Mr. Nasrallah’s comments amounted to an admission of guilt.

Then, on Thursday, Mr. Nasrallah held a remarkable news conference in which he said he knew the tribunal would soon issue indictments against Hezbollah members. Mr. Nasrallah said he had been told so by Mr. Hariri’s own son, Saad Hariri, the current prime minister. He added that Saad Hariri had essentially pardoned him in advance, declaring that the men to be accused were “undisciplined” members of Hezbollah with tenuous connections to the group.

Mr. Nasrallah clearly hoped to undercut any indictment, not only by breaking the news himself in advance, but by invoking Mr. Hariri, who has long been the tribunal’s chief supporter. Mr. Nasrallah’s gambit may work, some analysts say, because Mr. Hariri’s own political position has changed.

After his father’s death in 2005, Mr. Hariri emerged as the leader of an anti-Syrian political coalition that called for Hezbollah’s disarmament. But his movement, known as March 14 (the date of a vast anti-Syrian demonstration in 2005), gradually eroded as its Western allies moved toward engagement with Syria. After he became prime minister of a national unity government last year, Mr. Hariri bowed to political reality and began building a relationship with Damascus.

At the same time, the tribunal, which had released early reports that pointed to high-level Syrian involvement in the killing of Rafik Hariri, went quiet, and some of its witnesses recanted. More questions about the tribunal emerged last year after a judge released four senior Lebanese state security officers who had been held for four years in the Hariri killing but were not charged. Some have speculated that the tribunal’s prosecutors will charge Hezbollah members of playing accessory roles in the fatal car bombing, because they were unable to find enough evidence against the main perpetrators.

Mr. Hariri maintained a conspicuous silence on Friday, and on Saturday he gave a speech that emphasized the need to maintain national unity and better ties with Syria.

“The tribunal was a card to be played against Syria, and now it seems they’re trying to get rid of it,” said Elias Muhanna, the author of the Lebanese political blog Qifa Nabki. “It’s almost as if nobody wants to know who killed Hariri anymore.”

Even so, some analysts say any indictment of Hezbollah members would damage the group’s reputation.

“In this part of the world, when you say ‘this person is suspected’ and Hezbollah refuses to hand them over, everyone will believe Hezbollah is guilty,” said Sarkis Naoum, a columnist for the Beirut daily newspaper Al Nahar, which is aligned with the March 14 coalition.

Mr. Naoum also pointed out that while Mr. Nasrallah’s tone in Thursday’s speech was calmer than in previous speeches, his message was more aggressive. Mr. Nasrallah demanded that the March 14 faction acknowledge the mistakes it had made in recent years with its accusations against Syria and its allies.

Some analysts say Hezbollah is on the defensive for reasons that go well beyond the tribunal. Fears of another war with Israel have been on the rise in recent months, fueled by reports that Hezbollah obtained Scud missiles from Syria and tensions over the nuclear ambitions of Iran, Hezbollah’s chief patron. Mr. Nasrallah is aware that many Lebanese would blame Hezbollah for the damage inflicted in such a war, which is likely to be devastating. The country is still recovering from Hezbollah’s July 2006 war with Israel. In that context, Mr. Nasrallah’s need to discredit the tribunal and protect Hezbollah’s reputation from potential indictments is all the more urgent.