Tunisian soldiers guard the US embassy building in the capital Tunis on September 15, 2012.
The Tunisian health ministry says four people have lost their lives and nearly 50 sustained injuries during clashes between police and protesters at the US Embassy in Tunis.
Anti-US demonstrations over a low-budget anti-Islam film have been held all over the Muslim world, with protesters storming US embassies and torching US flags.
"Three protesters were shot dead, the fourth was hit by a car and 49 people were injured, including nine seriously," a spokesman for the ministry told AFP on Saturday.
The spokesman added that over 20 police officers were also among the injured.
Earlier, the ministry said two people were killed and almost 40 injured during Friday’s protests, which were sparked by the blasphemous film recently produced in the US.
On Saturday, the Tunisian interior ministry said it would punish all those protesters who attacked the US Embassy on Friday.
"Anyone closely or marginally involved in the events outside the American embassy in Tunis will be punished," national security spokesman Mohammed Ali Aroui said.
Muslims in Iran, Turkey, Sudan, Egypt, Yemen, Tunisia, Bangladesh, Indonesia, Malaysia, Kashmir, Pakistan, India, Iraq, Gaza, Morocco, Syria, Kuwait, Nigeria, Kenya, Australia, Britain, the United States, and some other countries have condemned the movie that denigrated Prophet Muhammad (PBUH).