According to Jews the seven laws of Noah only applies to humanity (non Jews) and prohibits committing murder this includes not killing Jews.
The 10 commandments in the Torah that only apply to Jews states; Thou shall not kill. This commandment implies Jews cannot kill other Jews, but allows the killing of non Jews.
Here are three commandments from the 613 commandments found in the written Tora which not only allows killing non Jews but demands it!
Mosheh ben Maimon, called Moses Maimonides and also known as RaMBaM, was a pre-eminent medieval Arab, Spanish, Sephardic Jewish philosopher, astronomer and one of the most prolific and influential Torah scholars and physicians of the Middle Ages. He was born in Córdoba (present-day Spain), Almoravid Empire on Passover Eve, 1135, and died in Egypt on December 12, 1204. He was a rabbi, physician, and philosopher in Morocco and Egypt.