The device had been left in a bag in the mausoleum in the Ain Rumana cemetery near the town of Muzaia, 70km southwest of Algiers.
It exploded on Friday afternoon as the cemetery was crowded with people praying for the dead during the Eid al-Adha (Day of Sacrifice) religious holidays, residents said.
Eid al-Adha is based on the story of the prophet Ibrahim sacrificing his son, Ismail, and marks the culmination of the Muslim pilgrimage Hajj.
Animals are sacrificed and prayers are held over a three day period of introspection and spiritual upliftment.
The funerals of the three women killed took place on Saturday.
According to an official toll and press reports, at least 34 people have been killed so far this year.
Violence in Algeria has claimed more than 15,000 lives since 1992 when the Islamic Salvation Front (FIS) won an overwhelming victory in elections, which were nullified after a military coup.
Press reports said on Saturday three people were killed in separate incidents in Algeria involving various groups.
In a separate incident a soldier had his throat slit when he was stopped at what was reported to be a fake roadblock at Adekar, 260km east of Algiers, and a young man was killed and two wounded when a group set on them with clubs at Kadiria, southeast of the capital, the report said.