30 June 2011 Last updated at 08:04 ET

Q&A: Hariri Tribunal

Rafik Hariri is widely credited with getting Lebanon back on its feet after the 15-year civil war

The UN-backed tribunal investigating the assassination of former Lebanese prime minister Rafik al-Hariri in 2005 has issued four arrest warrants, reportedly naming senior members of the Shia militant and political group Hezbollah.

There are fears that the country could be thrown into its worst political crisis in years as a result of the dispute over the tribunal. This in effect pits the Western-backed mainly Sunni coalition led by Saad Hariri - son of Rafik Hariri - against Hezbollah and its allies, backed by regional heavyweights Syria and Iran.

Hezbollah has repeatedly denied any involvement in the murder and threatened to retaliate if its members are implicated.

What is the Hariri tribunal?

The UN Security Council voted in 2007, at Lebanon's request, to set up the Special Tribunal for Lebanon (STL) to try those behind the 2005 assassination of former Prime Minister Rafik Hariri.

Hariri and 21 other people died when a massive blast ripped through his motorcade in central Beirut.

The tribunal, sitting in The Hague, was formally opened in March 2007. The court consists of 11 judges, seven international and four Lebanese.

Half of the tribunal's budget ($66m; £42m in 2011) comes from Lebanon's government.

What are its major findings?

In its early stages, the UN investigation, led by German judge Detlev Mehlis, implicated top-level Syrian security officials. Critics said the tribunal was part of US policy aimed at regime change in Syria.

However, under the current prosecutor, Daniel Bellemare, it appears that the tribunal is about to indict members of the powerful Lebanese Shia political and militant movement Hezbollah.

Both Hezbollah and Syria - which was forced to pull its troops out of Lebanon and relax its domination of its neighbour in the wake of the killing - have vehemently denied any role in the 2005 assassination.

Hezbollah, for its part, has dismissed the tribunal as an "Israeli instrument", and produced what it regards as evidence that Israel was involved in the assassination.

Why has the tribunal proved so divisive in Lebanon?

Hezbollah and its allies brought down Saad Hariri's government on 12 January

From the very start, the tribunal has been a political flashpoint in Lebanon, pitting the pro-Western Saudi-backed forces linked to Saad Hariri against Hezbollah and its allies, backed by Syria and Iran.

If - as expected - the tribunal implicates Hezbollah members in the assassination of Rafik Hariri, it would basically be accusing Lebanon's most powerful Shia group of involvement in the murder of the country's dominant political figure back in 2005.

There are widespread fears the indictments will trigger the kind of sectarian tensions which exploded in 2008, when Hezbollah fighters took over west Beirut and crushed pro-Hariri elements.

What has been the political fallout in Lebanon?

On 12 January, 11 Hezbollah-affiliated ministers resigned, bringing down the coalition government of then-Prime Minister Saad Hariri (Rafik Hariri's son).

The group, which denies any role in the killing, had wanted Mr Hariri to withdraw Lebanon's funding for the tribunal, stop all co-operation, and denounce the court's findings even before they were released. He had refused.

On 25 January, the Hezbollah-backed business tycoon, Najib Mikati, was appointed as the prime minister-designate, tilting the balance of power in Lebanon towards Syria and Iran, and away from the Western-allied bloc that had headed governments for nearly six years.

Five months later, after much political wrangling, Mr Mikati unveiled a new heavily pro-Syrian administration that critics have dubbed a "Hezbollah government".

What is the potential fallout in the wider Middle East?

Lebanon's largest political factions are generally split into Sunni and Shia camps that are closely allied to opposing Middle East powers.

Saad Hariri's backers, the US and Saudi Arabia, are engaged in a wider contest with the Shia power of Iran and its ally Syria, who support Hezbollah. Iran, Syria and Hezbollah are sworn enemies of Israel.

The interplay of these regional dimensions makes political instability in Lebanon, where Israel and Hezbollah fought a devastating war in 2006, potentially dangerous.

Setting aside their own differences, Saudi Arabia and Syria had tried for months to reach a compromise deal that preserved the country's delicate balance of power without wholly undermining the work of the tribunal. Iranian and Turkish officials had also tried to intervene. When the talks collapsed, Lebanese opposition groups accused the US of blocking the Saudi-Syrian deal.

As regional leaders from all sides appeal for calm, the crisis has so far been contained to a political one, although the threat of violence spilling over on to the streets of Lebanon is never far away.

What happens next at the tribunal?

Now that the STL has submitted the indictments and arrest warrants to the Lebanese prosecutor-general, the Lebanese authorities have 30 days to arrest the suspects named in the four warrants.

If they fail to do so, the STL will then make public the indictment and summon the suspects to appear before the court.

Analysts say Lebanese officials may be powerless to arrest the Hezbollah figures - if they are still in the country. Incoming Prime Minister Mikati has indicated that he will try to comply with international obligations while not jeopardising the country's security.