The trial of four Hezbollah members indicted in the 2005 fatal bombing of the former prime minister began last week before the Special Tribunal for Lebanon in The Netherlands.
The tribunal said through its official Twitter account two witnesses, firefighter Khaled Toubaili and an anonymous witness, testified Tuesday.
"The prosecution will not call any more witnesses this week," the tribunal said. "Tomorrow's hearing will only focus on procedural matters."
The anonymous witness testified via video link.
The Lebanese newspaper the Daily Star said Toubaili's testimony could shed light on the type of bomb used in the 2005 assassination. The report said the defense team suggests the explosion was triggered by an underground device while prosecutors say it was a car bomb.
Hezbollah, a Shiite movement and outspoken supporter of Syrian President Bashar Assad, denies involvement in the assassination. The former prime minister helped break Syria's dominance of Lebanon.