|The UN-backed tribunal is likely to be discussed during Saad Hariri's visit to Washington [Reuters]
Syria and Saudi Arabia have failed to broker an agreement aimed at easing political tensions in Lebanon over the international investigation into the assassination of Rafiq al-Hariri, a former prime minister.
The efforts by the two regional powers, who have previously backed rival blocs in Lebanon, had been seen as the best chance of avoiding unrest if, as expected, the UN-backed tribunal into the killing indicts members of the Shia Muslim Hezbollah movement.
However, Michel Aoun, the leader of the Free Patriotic Movement and Hezbollah allly, said efforts to reach a deal had come to a "dead end".
"The initiative has ended with no result," he told a news conference.
The impending indictments have paralysed Lebanon's unity government and raised fears of a repeat of the sectarian violence that killed 81 people in 2008.
Hezbollah, which has rejected allegations it was involved in the suicide bombing on the Beirut seafront in 2005 that killed Hariri and 22 others, blamed "American intervention and the inability of the other side to overcome American pressure" for the failure to reach a compromise.
When asked why the talks collapsed, Mohammed Fneish, a Hezbollah cabinet minister, said: "Ask Mrs Clinton," referring to the US secretary of state.
Cabinet meeting urged
Fneish said Hezbollah and its allies want an urgent cabinet meeting on Wednesday to discuss the issue.
"There is an opportunity between today and tomorrow," he said. If the meeting does not take place, Hezbollah and its allies will "decide on the next move".
However, Okab Sakr, a Shia politician close to Saad Hariri, the son of Rafiq al-Hariri and the current prime minister, said there had been no statement from Saudi Arabia or Syria on the status of their initiative.
He said that Hariri and Michel Suleiman, Lebanon's president, would continue efforts "to solve the crisis".
Hariri was in the US on Tuesday ahead of a meeting with Barack Obama, the US president, on Wednesday.
"Tomorrow, President Obama will meet with Prime Minister Saad Hariri of Lebanon to discuss US support for Lebanon's sovereignty, independence, and stability," Robert Gibbs, the White House spokesman, said in a statement.
The talks would also focus on "the ongoing work of the Special Tribunal for Lebanon (STL), and other regional issues," he said.