The silence on Friday was only broken by bells tolling from a nearby church, at which Kassir's funeral will be conducted on Saturday. The opposition, including Kassir's Democratic Left Movement, urged its supporters to attend the funeral procession.
During the tribute, journalists brandished pens and later sang the Lebanese national anthem as they stood near the Martyrs' Statue, which is riddled with bullet holes from the country's 15 years of civil war that ended in 1990.
The statue is in memory of a group of resistance leaders who were hanged by an Ottoman general in 1916 because they worked against Ottoman rule.
A television interviewer for the Lebanese Broadcasting Corporation, Shaza Omar, told Aljazeera.net that raising pens that bore Kassir's name meant that his pen couldn't be broken even after his death.
"His pen will continue to write, because we lost one Samir Kassir but there will be 1000 other Samir Kassirs," she said.
Omar voiced concern over what she saw as a threat to Lebanon's freedom of the press, saying that any Lebanese journalist could be murdered as Kassir was.
A journalist holds a picture of Samir
Kassir at the demonstration
However, she said that Kassir's assassination shouldn't stop journalists from uncovering the truth. "This is our mission as journalists, and we cannot stop doing it."
Columnist Ali Hamadeh, who works for the leading Lebanese daily An-Nahar, where Kassir also worked, described the slain journalist as a "true Arab liberal, not only a Lebanese liberal, and fighter for freedom".
Relations with Syria
Kassir had been working on a project to bring together intellectuals from Syria and Lebanon to discuss the future of relations between the two countries after the Syrian troop withdrawal from Lebanon that was completed on 26 April, Hamadeh said.
"And when you say intellectuals, it means freedom of speech, which is a threat to the dictatorship in Syria," Hamadeh said.
In one of his last articles, Kassir described Syrian workers in Lebanon as "being victims twice". He wrote that they were victims of a "regime that has failed to provide job opportunities for all its citizens, with no service offered to them at all except the hegemony of the intelligence that follows them even to where they work in Lebanon".
He wrote that Syrian workers were victims of Lebanese racism practiced against them because of the "miserable image which the Syrian regime gives about its citizens".
Telling the truth
Walid Shqeir, a Lebanon correspondent for the London-based pan-Arab al-Hayat newspaper, told Aljazeera.net that Kassir's murder aimed at "preventing any voice to say what is close to the truth – not even the entire truth".
Asked if he would be more cautious in his writings, Shqeir said: "Every journalist - even the most courageous - takes particular issues into consideration. But I think now journalists would insist more to telling the truth and to demand a political life that is more democratic."
Kassir had been monitored for years by the pro-Syrian Lebanese security services.
Kassir's widow, renowned interviewer Giselle Khouri, has reportedly called on France to take part in the investigation into her husband's killing, because he held French nationality.
Giselle Khouri, Samir Kassir's widow,
returned on Friday from the US
A UN spokesman in Beirut told Aljazeera.net that the commission that was designated by the UN Security Council to investigate the assassination of former Prime Minister Rafik al-Hariri would not look into the killing of Kassir.
The commission, Najib Friji said, had a "sole purpose, a sole mandate, which is to investigate the assassination of Rafik Hariri".
Many Lebanese say Syria continues to wield influence in Lebanon despite the troop withdrawal.
Friji said that the UN team set up by the Security Council to verify the withdrawal said in its report last month that it wasn't possible to verify the complete withdrawal of Syrian intelligence.