Many schools closed, while others suspended classes. But the call for a widespread strike came too late for many people to heed. Only a handful of shops were closed in Ashrafieh.

Kassir will be buried in Beirut Saturday.

Kassir was also a university professor and founding member of the Democratic Left Movement. Kassir has continually criticized Syria and the pro-Syrian Lebanese government and intelligence apparatus. In 2001 the Syrian-backed security services harassed Kassir, seized his passport and threatened him with arrest at Beirut airport. He was said to have received several death threats.

In his last column in An-Nahar on Friday, Kassir criticized the Syrian government for their unwillingness to enact rapid change.

Giselle Khoury, Kassir's wife, demanded an international investigation into her husband's death, Al-Arabiya satellite channel reported. Khoury was initially rumored to have been involved in Thursday's explosion, however it turns out she was in the United States at the time. Khoury works for Al-Arabiya as a journalist.

Pictures of the protest in downtown Beirut:

A Lebanese journalist holds a pen, symbolizing freedom of the press, as well as a picture of slain Lebanese journalist Samir Kassir

Lebanese journalists and politicians stand in silence in Martyrs' Square in downtown Beirut

Lebanese journalists and politicians stand in silence

Lebanese journalists hold pens and pictures of slain Lebanese journalist Samir Kassir

Head of Lebanese press syndicate Mohamed Baalbaki (L) holds a pen bearing the name of slain anti-Syrian journalist Samir Kassir during a sit-in

Lebanese journalists raise pens and black and white pictures of their assassinated colleague Samir Kassir during the demonstration

Lebanese journalists holds pens and posters of slain anti-Syrian journalist Samir Kassir

Gibran Tueni, managing editor of An-Nahar and newly elected MP, holding up a pen in honor of Samir Kassir

Lebanese journalists demonstrate at Martyrs' square in central Beirut to protest the killing of prominent opposition journalist Samir Kassir the day before

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