Washington on Friday issued a fresh warning to Syria to withdraw all its forces from Lebanon, voicing concern that Damascus was still interfering in its neighbour’s internal affairs and even had a “hit list” of opponents.

US President George W. Bush said he was “disturbed” by reports that Syrian intelligence agents remain in Lebanon, more than six weeks after Damascus was supposed to have pulled all its forces out of the country.

In Sunday’s round of the four-phase vote, the first since Syria ended its near three-decade troop presence, electors will choose 23 lawmakers -- 14 Muslims and nine Christians — in the Bekaa Valley and another 35 -- 25 Christians and 10 Muslims — in Mount Lebanon from a total of 262 candidates.

Unlike the first two rounds, which saw Muslims emerge comfortably on top, Christian candidates are gearing up for a fierce battle on Sunday, despite rifts in their own camp.

Christians are at odds among themselves after former exile and prominent Maronite Michel Aoun decided to forge an unlikely alliance with pro-Syrian candidates.

Polling booths were scheduled to open at 7:00 am (0400 GMT) until 6:00 pm (1500 GMT).

Lebanon’s Muslim community includes Sunnis, Shiites and Druze and represents 63 percent of the population. Christians — Catholics, Maronites and Greek Orthodox — account for the remaining 37 percent. The electoral law guarantees parliamentary parity between Christians and Muslims.

Retired Christian general and former exile Aoun and his Free Patriotic Current is running opposite Druze leader Walid Jumblatt and his anti-Syrian multi-confessional ticket as well as against other Christian candidates.

Aoun and one of his Christian opponents Nassib Lahoud, cousin and rival of pro-Syrian head of state Emile Lahoud, are both eyeing the presidency, should the president fall after the polls.

The fiercest battle of the third round is expected to take place in the Aley-Baadda district of Mount Lebanon between Aoun’s and Jumblatt’s candidates.

Jumblatt accused Syria of meddling in the elections through its agents — although Damascus was supposed to have withdrawn its troops late last month.

Bush said Friday he was disturbed by reports that Syrian intelligence operatives remain in Lebanon, in breach of a UN resolution ordering all Syrian forces out of the country.

“Our message to Syria — and it’s not just the message of the United States, the United Nations has said the same thing — is that in order for Lebanon to be free,” Syria needs to “not only remove their military, but to remove intelligence officers as well,” he said.

White House spokesman Scott McCellan said he was “deeply concerned about Syria’s interference and intimidation inside Lebanon” ahead of the polls.

UN Secretary UN Secretary General Kofi Annan ordered on Friday a UN verification mission back to Lebanon.

In the Bekaa, the coalition list between the Shiite militia Hezbollah and its former rival Amal are tipped to win in two districts, while Aoun’s list will run opposite Jumblatt’s coalition in the third.

Commentators and politicians have remarked on the democratic competition that would take place on Sunday’s polls unlike in the two previous rounds where the Amal-Hezbollah and Hariri’s electoral steamrollers guaranteed their landslide victories.

The pro-Syrian coalition in southern Lebanon grouping the Shiite Muslim Hezbollah and Amal movements took all 23 seats in the second round of the elections last Sunday.

In Beirut, the list headed by Saad Hariri, son of slain former prime minister Rafiq Hariri, snatched all 19 seats in the first round on May 29.

For the last leg of the elections on June 19, voters will cast their ballots in northern Lebanon for 28 seats.