Is it جائز to kill insects like mosquitoes and flies while in the state of الإحرام?

The ruling on killing insects during الإحرام depends on whether the creature is classified as harmful (mu'dhi) or harmless. Scholars unanimously agree that the muhrim (person in الإحرام) is permitted to kill harmful creatures, based on the hadith of Aisha in which النبي (صلى الله عليه وسلم) ordered the killing of five harmful creatures whether in the sacred precinct or outside it: the scorpion, the kite (bird of prey), the crow, the mouse, and the rabid dog. Scholars extended this ruling by analogy to include mosquitoes, wasps, snakes, and any creature that poses a threat to the الحاج.

الشيخ ابن عثيمين ruled that killing mosquitoes and other biting insects during الإحرام is جائز because they are harmful creatures, and the الحاج is not required to endure their harm. He noted that the general principle is that the muhrim is prohibited from hunting land game (sayd), but insects are not classified as game animals. الشيخ ابن باز similarly confirmed that swatting mosquitoes and killing harmful insects carries no penalty.

Regarding harmless insects such as ants and bees, scholars recommend avoiding killing them, both during الإحرام and outside it, as النبي (صلى الله عليه وسلم) prohibited the killing of ants, bees, hoopoes, and shrikes. However, even if a harmless insect is killed accidentally during الإحرام, no فدية is due. The key distinction scholars make is between land game (sayd al-barr) — which is explicitly prohibited for the muhrim — and insects, which are not classified as game.