A total of 1.25 million people are eligible to vote in the Mount Lebanon and eastern Bekaa Valley regions on Sunday in the penultimate stage of Lebanon's first national election without the presence of Syrian troops for three decades.
The most heated contests involve Christian leader Michel Aoun and his allies against a coalition, led by Druze leader Walid Jumblatt, in the central Baabda-Aley constituency and against a Christian alliance in the Byblos-Kesrwan district.
Aljazeera's correspondent in Lebanon, Ghassan bin Jiddo, reported that tensions in some districts had proven too much for some voters.
Fighting broke out in Bekaa, and some people have been injured.
Mutual accusations among participants have also emerged in the al-Matn area. Supporters of the Free National Trend alleged that some alliances have distributed money to voters in public - an accusation denied by all opposition parties.
Jumblatt, leader of the Progressive Socialist Party, also bitterly attacked Aoun.
In an interview with Aljazeera, Jumblatt said Aoun's return to Lebanon could cause instability.
"Aoun has begun his destruction plan," he said.
"Aoun should have stayed outside Lebanon instead of returning. His return was in accordance with an agreement with the Syrians and Lebanon's President Emile Lahoud," Jumblatt added.
Talal Arsalan, head of the Lebanese Democratic Party, criticised the government officials describing them as acting suspiciously.
"We have made up our decision to fight the severe campaign launched by those who have previously considered themselves as opposition parties, but are now represented in the authority and are leading the electoral process," Arsalan told Aljazeera.
These sides, including some ministers, are suspicious, he said.
"Scandals, such as distributing money, have publicly been taking place in the area since Saturday noon," he added.
About 100 candidates are competing in Mount Lebanon, with seats allocated to different sects according to Lebanon's power-sharing political system.
Thirty-five seats are up for grabs in Mount Lebanon and 28 in the Bekaa.
Two seats have been won uncontested in Mount Lebanon - Jumblatt and ally Marwan Hamadeh, both lawmakers in the outgoing parliament.
Seats in the first two rounds of voting, in Beirut and the south, for the most part were split almost evenly between opponents of Syria and supporters of the Islamist Hizb Allah resistance organisation.
Anti-Syrian forces need a strong showing in Sunday's vote in the central and eastern regions - at least 45 seats for a majority - to win a firm grasp on the 128-member parliament.
But the campaign has led to some surprising alliances and left some races too close to call.
The vote in central Mount Lebanon, the nation's most populous region, has been billed as the "mother of all battles" as it pits Jumblatt's allies against Aoun's.
Aoun, who fought and lost a war against Syria in 1989 before going into a 14-year exile, was one of Syria's main Lebanese foes, but recently broke with other opponents of Damascus and forged alliances with pro-Syrian politicians.
The anti-Syrian opposition also teamed up with Hizb Allah and the pro-Syrian Shia Amal in some districts.
Former exiled Christian General
Michel Aoun is hoping for victory
Aoun says his feud with Syria is over, now that Damascus has withdrawn from Lebanon. He is campaigning on a promise to fight the corruption he blames on Lebanon's economic ills, including a national debt of more than $30 billion.
In Metn, the former general has forged an alliance with pro-Syrian politician Michel Murr and Armenian political party Tashnag, against an anti-Syrian ticket, headed by legislator Nassib Lahoud and Pierre Gemayel, son of former President Amin Gemayel.
And in Bekaa, a list backed by Saad al-Din al-Hariri, son of assassinated former prime minister Rafiq al-Hariri, is facing off against pro-Syrian politicians.
Others in the anti-Syrian camp hope the elections, which end on 19 June with voting in the north, will finally end Damascus's control of the legislature.
Political tensions have spilled over into violence, and the government has sent army and police reinforcements to Mount Lebanon, the historic heart of the country.