The second round of nationwide municipal elections, widely seen as launching a new chapter in Lebanon's troubled history, turned into a showdown Sunday between the current prime minister and a former one.

Prime Minister Rafik Hariri and ex-Premier Omar Karami are not standing for election, but both have backed rival tickets in the port city of Tripoli, the country's second largest city after the capital, Beirut.The elections are set to fill 10,000 posts nationwide after the fourth and final round of voting in mid-June, and marks the first time major right-wing Christian groups have participated since the 1975-90 civil war.

Christian parties boycotted the 1992 and 1996 parliamentary elections to protest Syrian domination of Lebanon.

Nearly 600,000 people were eligible to vote Sunday across the North Province - including about 150,000 in Tripoli - to elect 2,247 mayors and village chiefs.

Figures for the turnout were not available when polls closed, and initial results are not expected until Monday.

Troops guarded outlying Christian towns and major intersections in this predominantly Muslim city of 400,000 to ensure safe balloting.

The first round of voting took place May 24 in the most populous province, Mount Lebanon. Elections in Beirut and southern and eastern regions are scheduled for the next two Sundays. No election will be held in an Israeli-occupied zone in the south.

In Mount Lebanon, Christian opposition politicians staged a comeback in some municipalities, and Shiite Muslim militants defeated government-backed candidates.

In Sunday's vote, newspapers predicted a tough race in Tripoli, and last minute attempts to head off a showdown foundered after Karami accused Prime Minister Hariri of election meddling.