Ministers held an emergency meeting late Thursday to discuss the killing of Samir Kassir.
Thousands of Lebanese held a candlelight march through central Beirut Thursday to remember Mr. Kassir.
He was killed when a bomb placed under his car blew up in mainly Christian East Beirut.
Opposition leaders immediately blamed the attack on Syria. Damascus denies the charge.
Mr. Kassir's newspaper columns frequently criticized Syrian influence in Lebanon. He helped organize the popular movement that helped bring an end to the Syrian military presence there.
A number of world leaders have condemned the killing. U.S. Secretary of State Condoleezza Rice called it a heinous act.
Some information for this story provided by AFP and Reuters.