The Lebanese government had been braced for trouble on what was declared a "day of rage" by activists who blamed the Friday car bombing that killed Major Gen. Wissam al-Hasan on the government of neighboring Syria.
Witnesses told CNN there were banners and chants denouncing Syria. Many demonstrators said they believe the bombing was a warning from Damascus to stop Lebanese support for anti-government rebels.
There was no word on any casualties in Sunday's clashes in Martyr's Square, and reports suggested the gunshots were police firing into the air to disperse the crowds.
The ceremony for Hasan took place at Beirut police headquarters and drew thousands of spectators, some of whom were bused in from other parts of the country. The Beirut Star said large posters of Hasan were hung from buildings and demonstrators waved flags of Lebanon and the Syrian opposition.
President Michel Sleiman spoke at the ceremony, saying Hasan had been targeted because the Information Branch he led had become increasingly effective in ferreting out terrorists. "This institution is being punished with the assassination of its leader, Major Gen. Wissam al-Hasan, because the Information Branch has achieved so much, including uncovering ... bomb plots where they confiscated explosives and arrested the transporter," Sleiman said.
Hasan's death could jeopardize the government formed last year after the collapse of the government under Prime Minister Saad Hariri, the Star said. Prime Minister Najib Mikati Saturday reneged on a previous decision to resign, giving President Michel Sleiman time to consult the National Dialogue Committee on the matter.