Candles and flags filled Martyrs Square, as thousands gathered just hours after Kassir was brutally murdered by a bomb planted in his car.

"They killed him because he worked for the democratic process in Lebanon and Syria," said Elias Khoury, a fellow founding member of the opposition Democratic Left movement.

The opposition also held a meeting in Beirut, and called for a general strike on Friday to mourn the murdered journalist.

Pictures from the vigil:

Opposition holds meeting:

Friends of the slain hero:

Lebanese author Elias Khoury (L) and Elias Attallah, head of the Democratic Left movement, mourn at the site of the car bomb explosion

A colleague of slain journalist Samir Kassir places a red rose on his desk after covering his seat with a Lebanese flag

Full coverage from Ya Libnan:
* So who murdered Samir Kassir?
* Lebanon protests another murder: Pictures from Martyrs' Square
* Lebanese Journalists pay tribute to murdered colleague
* Lebanon's murdered journalist: An open letter to the Lebanese
* Vigil held to honor slain journalist in Beirut
* France & Lebanon outraged for assassination of Lebanese Journalist
* Tragedy strikes again in Beirut
* Journalist targeted and killed in Beirut explosion
* Opposition blames Lahoud and Syria for latest assassination
* Anti-Syrian journalist murdered in Beirut
* Photographs of Samir Kassir's tragic crime scene

Sources: Ya Libnan, AP, Reuters, Yahoo