They were young, perhaps the youngest ever to try an armed attack against Israelis, and they were ready to die.

The arrest of three boys ages 12, 13 and 15, accused of trying to slip into Israel with homemade guns, sparked horror among their families and concern by Palestinian officials that militant groups have gone too far in their choice of recruits.

"That's absolutely unacceptable," said Palestinian Cabinet Minister Saeb Erekat (search). "Our children should have hope and a future and should not be suicide bombers. We want them to be doctors and engineers."

Israeli forces arrested the three Palestinian youths from the village of Tubas (search), near Nablus, on Thursday as they tried to cross a checkpoint, Israeli police spokesman Gil Kleiman said.

The boys said they planned to shoot people in the northern Israeli city of Afula, he said.

The army said it was still investigating the case and had not decided whether to charge the boys.

Palestinians have carried out thousands of attacks against Israelis during 41 months of violence, killing 930 people, while 2,688 have been killed on the Palestinian side, almost all in Israeli military strikes.

The boys, Jaffar Dababaat, 12, Tarek Abu Mahsen, 13, and Ibrahim Suafta, 15, left behind a letter saying they wanted to strike a blow against the barrier Israel is building in the West Bank. The note identified Tarek as a member of Islamic Jihad (search) and the other two as members of the Al Aqsa Martyrs' Brigades (search), a militant group linked to Yasser Arafat's Fatah movement.

"If we die, if we become martyrs, don't feel sorry for us. Just have a massive protest in our honor and distribute sweets to everyone," the letter said.

Tarek's parents were outraged and criticized Islamic Jihad for recruiting youngsters for an attack that would likely lead to their deaths.

"My son doesn't know how to write such a letter and never belonged to any groups. Someone older wrote this letter for him," said his mother, Amira Abu Mahsen.

"If it is proved that someone in specific sent them on this mission, I will make sure they are punished. They shouldn't send my young boy on such missions," said his father, Mohammed Abu Mahsen.

An Al Aqsa official who declined to be named strenuously denied the group had sent the boys. "This is impossible. I don't know where these kids came from," he said. Islamic Jihad spokesmen could not be reached for comment.

Criticism of attacks on Israelis is rare among Palestinians, but in recent months more people have been condemning the recruiting methods used by the militant groups.

In January, Hamas sent a mother of two young children as a suicide bomber to attack a crossing point between Gaza and Israel. Days earlier a 17-year-old bomber died when his bomb belt exploded prematurely, a week after his 15-year-old brother, Amjad, and a cousin were killed in clashes with Israeli forces.

But the ages of the Tubas youths was especially shocking for many.

Neither police nor the army knew if the would-be attackers were the youngest sent against Israel, but most militants are in their late teens or early 20s.

The three boys "don't have enough life experience to make such decisions," said Hafez Barghouti, editor of the Palestinian daily Al-Hayat Al-Jadida.

Barghouti said the use of youngsters to carry out attacks was on the rise, though he declined to speculate why. Others have said that as Israel has become more adept at stopping attacks, the militant groups have been forced to turn to people less likely to arouse suspicion.

The boys' parents found it hard to reconcile their image of their children with that of militants.

Amira Abu Mahsen said Tarek learned to love motorcycles from his father, a mechanic. He also kept birds as pets. "They were his greatest joy," she said.

His father recalled that a neighbor had told him that two strange men were looking for the boy about a week ago. Relatives said they were stunned to find out the boys had been arrested.

"We never thought he was ever involved in politics," said Jaffar's father, Hussein Dababaat, before he burst into tears.

"I lost my son," he said.