What is the meaning of "kill yourself" in quran 2:54?

>Sahih International: And [recall] when Moses said to his people, "O my people, indeed you have wronged yourselves by your taking of the calf [for worship]. So repent to your Creator and **kill yourselves**. That is best for [all of] you in the sight of your Creator." Then He accepted your repentance; indeed, He is the Accepting of repentance, the Merciful.(2:54) What is the meaning of "*and kill yourself*"?