Lebanese go to the polls on June 7 in a closely contested election that will pit an alliance including Hezbollah - the Syria-backed Shi'ite group that Washington designates a terrorist organisation - against an anti-Syrian coalition that holds a majority in parliament.

Mr Biden's office said the vice president, who has been on a tour this week to Serbia and Kosovo, would travel to Beirut on Friday to meet Lebanon's president, Michel Sleiman, Prime Minister Fouad Siniora, and Parliament Speaker Nabih Berri.

He would also join Lebanese Defence Minister Elias al-Murr in making an announcement on assistance to Lebanon's military, Mr Biden's office said, without giving any details.

Since the 2006 war between Hezbollah and Israel, the United States has expanded military aid to Lebanon to strengthen its armed forces as a counterweight to Hezbollah, the only Lebanese faction to remain armed after the 1975-1990 civil war.

US military assistance to Lebanon since 2006 has totalled more than US$400 million (S$580 million). It includes artillery, light weapons, vehicles, ammunition, tanks, and aerial drones.

Mr Biden, who will reiterate the United States' support for an independent and sovereign Lebanon, follows in the footsteps of US Secretary of State Hillary Clinton, who visited in April to urge Lebanese to hold open and fair elections.

Many Lebanese analysts predict a small swing in the June vote toward Hezbollah and its allies, but there is no reliable opinion polling.

At the time of Mrs Clinton's visit, Hezbollah criticised it as interference in Lebanese affairs, so it is likely to view Mr Biden's visit with equal annoyance.

US-led international pressure and domestic protests forced Hezbollah's backer Syria to end 29 years of military presence in Lebanon after the assassination of former Lebanese Prime Minister Rafik al-Hariri in 2005. -- REUTERS