First: The default principle in Islam is the sanctity of life, as indicated by the verse:
“And do not kill yourselves.” [An-Nisa 4:29]
Preserving life is one of the maqāṣid (objectives) of Islamic law, and in many instances, it takes precedence over other objectives, including the preservation of religion.

Accordingly, it is forbidden for a Muslim to take their own life or to intentionally harm themselves entirely or partially, except in cases explicitly permitted by Islamic law. Killing oneself is considered a major sin.

Second: There is a clear distinction between suicide, which is the act of killing oneself, and plunging into the enemy with the intent of engaging in jihād or defense:

• Suicide is a deliberate act of causing one’s own death, typically driven by despair, which is often attributed to mental illnesses such as depression, bipolar disorder, schizophrenia, alcoholism, or drug abuse. It is generally the result of a psychological or emotional disorder.
• Engaging in fight fiercely with the enemy, however, is a form of jihād and refers to direct engagement with the enemy, where the risk of martyrdom and death is higher than usual.
  For instance, being part of the first attacking waves in war, carrying out special forces missions behind enemy lines, or conducting reconnaissance in dangerous areas all fall under this category. These actions involve close engagement with the enemy and carry significant risk.

This type of action is supported in Islam, and examples include:

1. Ṣuhayb (may Allāh be pleased with him) left Mecca for Medina alone to migrate to the Prophet (peace and blessings be upon him). When the polytheists caught up with him, he drew his arrows and said: “By Allāh, none of you will approach me without me shooting him.” He was prepared to fight them alone and said, “If you want my wealth in Mecca, take it, and I will tell you where it is.” When he reached the Prophet (peace and blessings be upon him), the Prophet said: “You have made a profitable trade, O Abū Yaḥyā.” Then the verse was revealed: “And among the people is he who sells himself seeking Allāh’s pleasure.” [Al-Baqarah 2:207]
2. In the ḥadīth regarding righteous deeds during the first ten days of Dhul-Ḥijjah, the Prophet (peace and blessings be upon him) made no exception except: “A man who went out with himself and his wealth, and did not return with any of it.” In another narration: “Whose horse was injured and his blood was spilled.”
3. Imam ᾽Aḥmad reported with his chain that a man attacked the enemy alone. People said, “He has led himself to destruction.” But ῾Umar (may Allāh be pleased with him) responded: “No, rather he is of those about whom Allāh said: ‘And among the people is he who sells himself seeking Allāh’s pleasure, and Allāh is kind to the servants.'” [Al-Baqarah 2:207]
4. Also cited is the story of the Boy and the King (from the People of the Ditch), where the boy sacrificed himself for the sake of religion—a well-known and authentic story.
5. Likewise, Al-Barā᾽ ibn ῾Aāzib in the Battle of Yamāmah, who was thrown over the wall into the enemy’s midst alone in order to open the gate from inside.

Such actions are a form of warfare and humiliating the enemy, and they occur among both Muslims and non-Muslims.

For example, the Japanese frequently used such tactics during World War II. The Allies did similarly in Operation Market Garden, where thousands of soldiers were dropped behind German lines in the Netherlands, resulting in heavy casualties.
Similarly, in the 1973 war against the Zionists, the first waves to cross the Suez Canal were essentially sacrificial missions. The Soviets estimated that 25,000 out of 80,000 attempting the crossing would be killed.

All of this is considered engaging in fight fiercely with the enemy—a type of warfare and sacrifice. The fighter dedicates himself to a cause he believes in, and in Islam, he hopes to be counted among the martyrs before Allāh.

As for the question posed—it falls under the category of siyāsah shar῾īyyah (legal policies). There is no fixed general ruling; rather, it depends on the circumstances of conflict and warfare. Those directly involved in the situation are the ones best suited to issue rulings. A person not in the battlefield should not issue a fatwā for a fighter, nor should someone far away issue rulings for someone close to the scene.

The principle is: “No one may assume leadership over another while being in the latter’s home or under their authority.”

Thus, rulings are determined by the people of each region according to their circumstances.

However, we must emphasize that anyone living among people in peace or in a land where he has a covenant of safety must never undertake such actions that harm innocents. Doing so is a betrayal and a violation of the sanctity of life, and the perpetrator is guilty of the major sin of murder. No excuse or misinterpretation can justify it.

This is the situation in most of the world today, and only actual war zones are excluded.

Likewise, what some extremists carry out and label as martyrdom, involving the killing of innocent people and the destruction of the land—all of this is forbidden and criminal behavior. It reflects the ideology of the Khawārij and Daesh (ISIS) about whom the Prophet (peace and blessings be upon him) said: “If I were to meet them, I would kill them like the people of ‘Aad were killed.”

Fatwā issued by Dr. Khālid Naṣr