Islamic military jurisprudence
This view of al-Shafi'i is mitigated by the fact that an opposite view, in agreement with the majority, is also attributed to al-Shafi'i.
According to Abdulaziz Sachedina, offensive jihad raises questions about whether jihad is justifiable on moral grounds. He states that the Qur'an requires Muslims to establish just public order, increasing the influence of Islam, allowing public Islamic worship, through offensive measures. To this end, the Qur'anic verses revealed required Muslims to wage jihad against unbelievers who persecuted them. This has been complicated by the early Muslim conquests, which he argues were although considered jihad by Sunni scholars, but under close scrutiny can be determined to be political. Moreover, the offensive jihad points more to the complex relationship with the "People of the book".
Some major modern scholars who have rejected the idea of "offensive jihad" include the founder of the Muslim Brotherhood, Hasan al-Banna (1906–1949), the Al-Azhar scholar Muhammad Abu Zahra (1898–1974) who thought that "military jihad is permitted only to remove aggression ('udwân) and religious persecution (fitnah) against Muslims", as well as Syrian scholars Mohamed Said Ramadan Al-Bouti (1929–2013) and Wahbah al-Zuhayli (1932-2015), the latter saying that "peace is the underlying principle of relations between Muslims and non-Muslims. al-Zuhayli maintains that this view is supported by 8:61, as well as 2:208 and 4:94 that establish the principle of international peace. For him, Muslims should be committed to peace and security (on the basis of 4:90 and 60:8)."

International conflict: International conflicts are armed strifes conducted by one state against another, and are distinguished from civil wars or armed strife within a state. Some classical Islamic scholars, like the Shafi'i, classified territories into broad categories: dar al-islam ("abode of Islam"), dar al-harb ("abode of war), dar al-ahd ("abode of treaty"), and dar al-sulh ("abode of reconciliation"). Such categorizations of states, according to Asma Afsaruddin, are not mentioned in the Qur'an and Islamic tradition.

Declaration of war: The Qur'an commands Muslims to make a proper declaration of war prior to the commencement of military operations. Thus, surprise attacks prior to such a declaration are illegal under the Islamic jurisprudence. The Qur'an had similarly commanded Muhammad to give his enemies, who had violated the Treaty of Hudaybiyyah, a time period of four months to reconsider their position and negotiate. This rule, however, is not binding if the adversary has already started the war. Forcible prevention of religious practice is considered an act of war.

Conduct of armed forces: During battle the Qur'an commands Muslims to fight against the enemy. However, there are restrictions to such combat. Burning or drowning the enemy is allowed only if it is impossible to achieve victory by other means. The mutilation of dead bodies is prohibited. The Qur'an also discourages Muslim combatants from displaying pomp and unnecessary boasting when setting out for battle.
According to professor Sayyid Dāmād, no explicit injunctions against use of chemical or biological warfare were developed by medieval Islamic jurists as these threats were not existent then. However, Khalil al-Maliki's Book on jihad states that combatants are forbidden to employ weapons that cause unnecessary injury to the enemy, except under dire circumstances. The book, as an example, forbids the use of poisonous spears, since it inflicts unnecessary pain.

Civilian areas: According to all madhhabs, it is not permissible to kill women or children unless they are fighting against the Muslims. The Hanafi, Hanbali and Maliki schools forbid killing of those who are not able to fight, including monks, farmers, and serfs, as well as mentally and physically disabled.
Harming civilian areas and pillaging residential areas is also forbidden, as is the destruction of trees, crops, livestock and farmlands. The Muslim forces may not loot travelers, as doing so is contrary to the spirit of jihad. Nor do they have the right to use the local facilities of the native people without their consent. If such a consent is obtained, the Muslim army is still under the obligation to compensate the people financially for the use of such facilities. However, Islamic law allows the confiscation of military equipment and supplies captured from the camps and military headquarters of the combatant armies.
However, 14th century Fiqih Ibn Hudayl of Granada says:

It is permissible to set fire to the lands of the enemy, his stores of grain, his beasts of burden—if it is not possible for the Muslims to take possession of them—as well as to cut down his trees, to raze his cities, in a word, to do everything that might ruin and discourage him, provided that the imam deems these measures appropriate, suited to hastening the Islamization of that enemy or to weakening him. Indeed, all this contributes to a military triumph over him or to forcing him to capitulate.

Negotiations: Commentators of the Qur'an agree that Muslims should always be willing and ready to negotiate peace with the other party without any hesitation. According to Maududi, Islam does not permit Muslims to reject peace and continue bloodshed.
Islamic jurisprudence calls for third party interventions as another means of ending conflicts. Such interventions are to establish mediation between the two parties to achieve a just resolution of the dispute.

Ceasefire: In the context of seventh century Arabia, the Qur'an ordained Muslims must restrain themselves from fighting in the months when fighting was prohibited by Arab pagans. The Qur'an also required the respect of this cease-fire, prohibiting its violation.
If, however, non-Muslims commit acts of aggression, Muslims are free to retaliate, though in a manner that is equal to the original transgression. The "sword verse", which has attracted attention, is directed against a particular group who violate the terms of peace and commit aggression (but excepts those who observe the treaty). Patricia Crone states that this verse seems to be based on the same above-mentioned rules. Here also it is stressed that one must stop when they do. Ibn Kathir states that the verse implies a hasty mission of besieging and gathering intelligence about the enemy, resulting in either death or repentance by the enemy. It is read as a continuation of previous verses, it would be concerned with the same oath-breaking of "polytheists".

Prisoners of war: Men, women, and children may all be taken as prisoners of war under traditional interpretations of Islamic law. Generally, a prisoner of war could be, at the discretion of the military leader, executed, freed, ransomed, exchanged for Muslim prisoners, or kept as slaves. In earlier times, the ransom sometimes took an educational dimension, where a literate prisoner of war could secure his or her freedom by teaching ten Muslims to read and write. Some Muslim scholars hold that a prisoner may not be ransomed for gold or silver, but may be exchanged for Muslim prisoners. Women and children prisoners of war cannot be killed under any circumstances, regardless of their religious convictions, but they may be freed or ransomed. Women who are neither freed nor ransomed by their people were to be kept in bondage - also referred to as malakah.
Kitab al-Umm of Al-Shafi'i also recorded how Zubayr ibn al-Awwam and Anas ibn Malik convinced Umar to pardon Hormuzan, despite Umar earlier intent to execute the Persian general for the death of his two precious soldiers, Mujaz'ah ibn Thawr as-Sadusi and al-Bara' ibn Malik. Umar in the end agreed with Zubayr and Anas to spare Hormuzan as prisoner of war, and this historical rulings of Zubayr, Anas, and caliph Umar became the guideline for Shafiite scholars that prisoner of war in normal condition are not allowed to be harmed.

Permission to interrogate & torture: However, there are special condition regarding the allowance the conduct of using torture as method of interrogation, 

Ibn Taymiyyah, Hanbalite scholar who has been praised as Mujaddid, has issued Fatwa that using torture on certain case for exceptionally dangerous criminal or enemy of the state were allowed, which based on the conduct of Zubayr ibn al-Awwam, when he tortured the Jewish chieftain Kenana ibn al-Rabi in the aftermath of the conquest of Khaybar fortresses, as Kenana was hiding the war spoils in Khaibar and refused to tell it. Abd al-Aziz Bin Baz, late 19th AD Grand Mufti of Saudi also supported Ibn Taymiyyah fatwa and issued his own fatwa with similar ruling on the basis Zubayr conduct of interrogating Kenana. Ibn Baz highlighted Zubayr conduct were acknowledged and permitted by Muhammad, as Kenana was one of Jewish conspirator in Khaybar.