Security camera footage has been released of the gunmen walking through the Tunis museum during an attack that left 21 people dead.
The one-minute video posted on the government's Interior Ministry's Facebook page shows the two men calmly walking through the National Bardo museum, carrying assault rifles and bags.
At one point they encounter another man with a backpack walking down a flight of stairs. They briefly acknowledge each other before they walk on in opposite directions. There was no explanation of who the third man was.
One of the attackers is wearing a baseball cap and a heavy jacket, while the other has a red hoodie and tracksuit pants.
The video also shows stills of the dead gunmen, including a picture indicating that at least one was wearing an explosive belt.
Among the 21 dead in Wednesday's attack, 17 were cruise ship tourists, including British mother-of-two Sally Adey.
The two gunmen were killed in a firefight with security forces.
The Islamic State group based in Iraq and Syria has claimed the attack. Several well-armed groups in Libya have pledged allegiance to IS.
Police in Tunisia have arrested five people described as directly tied to the two gunmen. Four others said to be supporters of the cell were also arrested in central Tunisia, not far from where a group claiming allegiance to al Qaida's North African branch has been active.
IS issued a statement and audio on jihadi websites applauding the dead gunmen as "knights" for their "blessed invasion of one of the dens of infidels and vice in Muslim Tunisia".
Several well-armed groups in neighbouring and chaotic Libya had already pledged their allegiance to IS.