Sacred Months
Fighting in the sacred months is serious, but retaliation is allowed. If they attack you, then respond in kind. However, be mindful of Allah and know that He is with those who are conscious of Him.
2:194The forbidden month for the forbidden month, and forbidden things in retaliation. And one who attacketh you, attack him in like manner as he attacked you. Observe your duty to Allah, and know that Allah is with those who ward off (evil).