( BBC ) - Lebanon is preparing to mark three years since the assassination of former PM Rafik Hariri, as the funeral is held of Hezbollah commander Imad Mughniyeh.
The two high profile events are to take place just a few miles apart in Beirut.
A huge security operation is under way in the capital amid fears of clashes between pro- and anti-Syrian factions.
Correspondents say it comes at a potentially explosive time in Lebanon; the country has had no president since November and no functioning parliament.
The country has been experiencing some of its worst internal violence since the assassination of Rafik Hariri plunged Lebanon into crisis three years ago.
His murder sparked massive domestic and international pressure, which forced Syria to withdraw its troops from neighbouring Lebanon after a presence of 29 years.
Tens of thousands of Lebanese are expected to converge on Martyrs' Square in Beirut's city centre where Mr Hariri is buried.
The BBC's Mike Sergeant in Beirut says in recent days the political rhetoric has been getting sharper on all sides - add into the mix heightened emotions following the killing of Imad Mughniyeh on Tuesday in a car bombing in the Syrian capital, Damascus. His body is now back in Lebanon and a large crowd is also expected at his funeral in the Hezbollah stronghold in the southern suburbs of Beirut.
The US welcomed the killing of the Hezbollah commander implicated in numerous bomb attacks and a wave of hostage-taking in Lebanon in the 1980s.
A US state department spokesman said the world would be a "better place" without Imad Mughniyeh, whom he called a "mass murderer and a terrorist".
Hezbollah and Iran have blamed Israel for his killing, but it has denied any involvement.
The Syrian government also condemned the "cowardly terrorist act" and said investigations were still under way to find the perpetrators.
Mughniyeh, in his late 40s, had been variously described as special operations or intelligence chief of Hezbollah's secretive military wing, the Islamic Resistance.
He had been top of the US Most Wanted list until he was replaced by Osama Bin Laden and other al-Qaeda leaders following the 11 September 2001 attacks.
Analysts say his death will be a significant blow to Hezbollah, which battled Israel in the 2006 Lebanon war, with help from its Iranian and Syrian backers.
Hezbollah was founded in 1982 by a group of Shia Muslim clerics after the Israeli invasion of Lebanon. It has emerged in recent years as a major political and military force in Lebanon, after military successes against Israel.