相关规则
Switzerland
Practice Relating to Rule 2. Violence Aimed at Spreading Terror among the Civilian Population
Switzerland’s Basic Military Manual (1991) states:
It is prohibited to commit acts of violence or to threaten violence with the primary aim of spreading terror among the civilian population. The threat of nuclear attack against urban centres is contrary to the Additional Protocols. 
Switzerland, International Humanitarian Law in Armed Conflict, with reference to the Swedish Total Defence System, Swedish Ministry of Defence, January 1991, Article 27(2) and commentary.
Switzerland’s Penal Code (1937), taking into account amendments entered into force up to 2011, states under the title “Felonies and misdemeanours against public peace”:
Art. 260quinquies
1 Any person who collects or provides funds with a view to financing a violent crime that is intended to intimidate the public or to coerce a State or international organization into carrying out or not carrying out an act shall be liable to a custodial sentence not exceeding five years or to a monetary penalty.
4 Paragraph 1 does not apply if the financing is intended to support acts that do not violate the rules of international law applicable to armed conflicts. 
Switzerland, Penal Code, 1937, taking into account amendments entered into force up to 2011, Article 260quinquies (1) and (4).
Switzerland’s ABC of International Humanitarian Law (2009) states: “Even in war not everything is allowed. Various means and methods are prohibited, including … spreading terror”. 
Switzerland, Federal Department of Foreign Affairs, ABC of International Humanitarian Law, 2009, p. 29.
The publication further states:
The concept of “terrorism” has not yet been defined in International law. International law, Human rights and international humanitarian law nonetheless do prohibit many terrorism related acts and activities. In fact, according to international humanitarian law, acts generally considered as acts of terrorism, such as strikes against the civilian population or Civilian Objects, indiscriminate attacks or hostage taking, are prohibited both in international and non-international armed conflict. Moreover, international humanitarian law explicitly prohibits acts or threats of violence the primary purpose of which is to spread terror among the civilian population. 
Switzerland, Federal Department of Foreign Affairs, ABC of International Humanitarian Law, 2009, p. 39.
[emphasis in original]
In 2010, in its Report on IHL and Current Armed Conflicts, Switzerland’s Federal Council stated:
3.3 Increasing use of guerrilla tactics…
The appearance of non-State actors technically inferior to their government adversaries has favoured the growth of guerrilla tactics. … With this in mind, the civilian population is of a twofold interest in the eyes [of the weaker of the adversaries], on one hand as a place of retreat and combat base, on the other hand as a target of attacks.
Even if the civilian population provides important support to the insurgents, it is nevertheless made the object of terrorist acts (direct attacks, pillage, hostage-taking) … under the guise of punitive actions, intimidation, propaganda or to incite ethnic or religious tensions. …
International humanitarian law in force treats these cases in a relatively complete manner, binding non-State and State actors alike. …
International humanitarian law also clearly prohibits attacks against the civilian population. This also applies to abductions, suicide attacks against markets, mosques or schools, as well as torture and other acts of terrorism. Only attacks against military objectives come within the framework of international humanitarian law, even if these take the form of suicide attacks. 
Switzerland, Federal Council, Report on IHL and Current Armed Conflicts, 17 September 2010, Section 3.3, pp. 11–12.
[footnotes in original omitted]
In 2012, Switzerland’s Federal Department of Foreign Affairs issued a press release entitled “Appeal by the Swiss authorities for compliance with international humanitarian law in Syria”, which stated:
International humanitarian law is applicable to non-international armed conflict.
4. International humanitarian law is applicable in non-international armed conflicts. All parties to the conflict are therefore obliged to respect its rules in all circumstances, including the rules protecting persons who are [not] or are no [longer] participating in the hostilities, as well as the rules relative to the means and methods of warfare.
Appeal to respect international rules
7. … Moreover, international humanitarian law proscribes the act of spreading terror among the civilian population. 
Switzerland, Federal Department of Foreign Affairs, “Appeal by the Swiss authorities for compliance with international humanitarian law in Syria”, Press Release, 15 November 2012.