JERUSALEM — A 12-year-old Palestinian girl who was imprisoned after she confessed to planning a stabbing attack in a West Bank settlement will be released early, Israel’s prison service said Monday, capping a saga that drew attention to the dual legal system in the West Bank.

The case has put Israel’s military justice system in a tough spot as it deals with a girl who has pleaded guilty to a crime, yet has not even completed the seventh grade. She is believed to be the youngest female Palestinian ever sent to an Israeli prison.

According to court documents provided by the military, the girl, whose name could not be published because of her age, approached the West Bank settlement of Carmei Tsur on Feb. 9 with a knife hidden under a shirt.

A security guard ordered her to halt, and a resident instructed her to lie on the ground and told her to give up the knife, which she did.

An amateur video clip provided to Israeli TV showed the resident asking the girl, who was wearing her school uniform, whether she had come to kill Jews, and she said yes. She later pleaded guilty to attempted manslaughter in a plea bargain and was sentenced to 4½ months in prison.

Last week, the girl’s family appealed to Israeli military and prison officials to release her, citing her age.

‘‘Prison is not a place for a small child,’’ said Abeer Baker, one of the girl’s lawyers. ‘‘If it was a Jewish girl, she wouldn’t stay in prison for even one hour because it is forbidden according to the Israeli law.’’

Palestinian residents on the West Bank are subject to military law that can sentence suspects as young as 12 to prison.

By contrast, Israeli settlers, as well as Jewish and Arab citizens of Israel, are subject to Israeli civil law, which does not allow anyone under 14 to go to prison.

Palestinian residents of East Jerusalem, which Israel annexed after the 1967 war, are also subject to Israeli civil law. Last week, for example, the Ynet news site reported that an 11-year-old Palestinian boy from Jerusalem convicted in a stabbing on the city’s light rail has been sent to a juvenile facility run by Israeli social services.

According to Israel’s prison service, 437 Palestinian minors were in Israeli prisons as of Feb. 29, the most recent date that statistics were available. Of those, 12 were female.

The 12-year-old was the only girl under age 14, according to the data. In addition, four Palestinian boys under 14 were in Israeli prisons. The Israeli human rights group B’Tselem said it was not familiar with any other instance in which a girl so young was imprisoned.

Associated Press