It was narrated from Ibn 'Umar that:

the Messenger of Allah commanded that dogs be killed, except those which were exempted.

أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم أَمَرَ بِقَتْلِ الْكِلاَبِ غَيْرَ مَا اسْتَثْنَى مِنْهَا ‏.‏