Hundreds of thousands of Lebanese swarmed into Beirut today for a mass rally called by the Shia Muslim group Hezbollah to denounce Western interference in the country and global demands for Syria to pull out its troops.

The rally attracted Shia Muslims and others to a central Beirut square only 300 metres from where opposition protesters, mostly Christians, have held much smaller almost daily rallies to demand a complete Syrian withdrawal.

Streams of buses, pick-up trucks and cars jammed main roads into the capital, black-clad Hezbollah militants joined tens of thousands crowded into the central Riad Solh Square in the heart of Beirut, chanting "Beirut is free, America out".

Estimates of the crowd ranged up to half a million - one in eight of Lebanon's population - although Lebanese television reported that Syria was bussing in supporters to boost the numbers. The size of the rally highlighted the continuing divisions in Lebanon 15 years after the end of its long civil war.

Sources said that Syria's 14,000 troops today began the first phase of a two-stage withdrawal from the country, redeploying to the eastern Bekaa valley near the Syrian border. No timetable has been given for the final pull-out, although one official Syrian source told Reuters today that it come come soon, and would include all security and intelligence personnel.

"Lebanon isn’t your playground," was the slogan on one poster bearing a picture of President Bush, who has been leading international calls for Syria to withdraw its troops from Lebanon. The square was dotted with red-and-white national flags that have become a symbol of rival rallies by anti-Syrian opposition forces.

Lebanese army Jeeps and armoured vehicles were lined up to separate the pro-Syrian demonstrators from neighbouring Martyrs’ Square which has been filled almost daily with rival opposition supporters chanting "Syria out". Protesters waved portraits of Hafez al-Assad, the late Syrian president, and his son and successor Bashar.

"We are going to protest to voice our condemnation of the UN resolutions and support the resistance. Neither Bush nor the UN can decide what sort of life and government we want," declared Hussein Faqih de Kafra, 24.

Sheikh Hassan Nasrallah, the Hezbollah chief, has rejected UN Security Council Resolution 1559 which demands the immediate pullout of foreign troops from Lebanon and the disarming of militias on its territories.

"We have the right to reject the international resolution because it is a blatant interference in our internal affairs and all its clauses are free services to the Israeli enemy," he said.

Syrian forces are credited in Lebanon with helping end the 1975-90 civil war which tore Lebanon apart. About 150,000 people were killed as Christian, Muslim and Druze militants fought each other in successive rounds of violence.

But Syria's role in Lebanon has come under fierce attack since a bomb attack killed Rafik al-Hariri, a former prime minister, on February 14. Syria denies any involvement in the blast.

But the prospect of a Syrian disengagement from Lebanon poses a challenge to Hizbollah and its military wing, which enjoy Syrian protection and patronage.

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