The ministry said in a statement that the toll was a “preliminary estimate” for the attack in Issers, some 35 miles east of the capital, Algiers.
Interior Minister Yazid Zerhouni, who went to the scene, called the bombing “an act against Algerians.”
“It’s utter carnage,” the father of one of those killed in the attack told the official news agency APS. “May God punish them for the crime they have committed against these youngsters, and their country,” he said, weeping.
The local al-Qaida affiliate has claimed several attacks in the past, including the suicide bombings of United Nations offices and a court building in Algiers in December, which killed 41 people.
“Most of the dead [on Tuesday] were young men aged between 18 and 20. They were in line waiting to enter the school for recruiting exams when they were mowed down by the blast,” a witness told Reuters by telephone.
“The car explosion destroyed part of the outer wall of the school and blew a huge crater into the ground, about three meters from the main gate,” he added.
As well as devastating the entrance to the school, the blast destroyed several nearby houses, blew out windows in nearby shops and tore up trees.
Tuesday’s bombing came two days after a militant ambush in Skirda, about 300 miles east of Algiers, that targeted the military commander of the region and his police escort. Twelve people died in that attack, according to local media.
The reports said suspected Islamic militants detonated road mines and opened fire on the convoy. They beheaded the victims and stole their uniforms and automatic rifles.
In a similar attack three days earlier, militants killed the military chief for the Jijel area, also east of Algiers, local media reported.
On August 9, a suicide bomber rammed a van full of explosives into a police post at the beach resort of Zemmouri el-Bahri, killing eight people and injuring 19 others.
Less than a week earlier, on August 3, another suicide attack on police in Tizi Ouzou wounded 25 people.
Responsibility for that attack was claimed by al-Qaida’s North African branch.
They also claimed a July 23 attack in which police said a suicide bomber on a motorbike injured 13 Algerian soldiers in Lakhdaria, also east of Algiers.
These attacks ended a six-month period of calm that followed the devastating December bombings in Algiers.