A mother and her baby at the rally. (Reuters)

Beirut, March 14 (Reuters): Hundreds of thousands of anti-Syrian protesters flooded central Beirut today in what witnesses said was Lebanon?s biggest demonstration since former Prime Minister Rafik al-Hariri?s killing exactly a month ago.

Flag-waving crowds from across Lebanon packed the capital?s Martyrs? Square, near Hariri?s grave, and swamped nearby areas to demand an international inquiry into his death, the sacking of Syrian-backed security chiefs and a total Syrian pullout.

In contrast to previous anti-Syrian protests since a bomb blast killed Hariri on February 14, many Sunnis joined Druze and Christians in taking to the streets. Hariri was a Sunni. ?We demand to know who killed Rafik al-Hariri,? said Mustapha Mrad, a Sunni demonstrator carrying a Lebanese flag.