False flag
As a tactic to undermine political opponents: 

Operation TPAJAX: On 4 April 1953, the CIA was ordered to undermine the government of Iran over a four-month period, as a precursor to overthrowing Prime Minister Mohammad Mosaddegh. One tactic used to undermine Mosaddegh was to carry out false flag attacks "on mosques and key public figures", to be blamed on Iranian communists loyal to the government.
The CIA operation was code-named TPAJAX. The tactic of a "directed campaign of bombings by Iranians posing as members of the Communist party", involved the bombing of "at least one" well known Muslim's house by CIA agents posing as Communists. The CIA determined that the tactic of false flag attacks added to the "positive outcome" of TPAJAX.
However, as "the C.I.A. burned nearly all of its files on its role in the 1953 coup in Iran," the true extent of the tactic has been difficult for historians to discern.

Operation Susannah: In the summer of 1954, a group of Egyptian Jews recruited by Israeli army intelligence were caught with plans to bomb American, British, and Egyptian civil targets in Egypt. The bombs were timed to detonate several hours after closing time. The bombings were to be blamed on the Muslim Brotherhood, Egyptian Communists, "unspecified malcontents", or "local nationalists", with the aim of creating a climate of sufficient violence and instability to induce the British government to refrain from evacuating its troops occupying Egypt's Suez Canal zone, a move that would embolden Egyptian President Nasser against Israel. However, the plot was exposed before launch and Egyptian authorities were able to tail an operative to his target, arrest him and later search his apartment where the entire plan, including the names of other agents and explosive materials, was held. Unknown to Israel Prime Minister Moshe Sharet, the exposé caused a scandal in Israel, with Israeli officials blaming one another for the operation and the Israeli defense minister, Pinhas Lavon, resigning under pressure. Later, two investigative committees found that Lavon was unaware of the operation.

Failed operations: Due to its deceptive nature a false flag operation can fail in such a manner as to implicate the perpetrator rather than the intended victim.
A notable example is an April 2022 FSB operation where would-be Ukrainian assassins of Russian propagandist Vladimir Solovyov were filmed while being arrested. The footage published by the FSB was however found to implicate the FSB as having staged the arrest. Together with weapons, drugs, Ukrainian passports and Nazi memorabilia the footage also prominently showed three expansion packs for the Sims 3 video game. Investigative journalist Eliot Higgins interpreted this to mean that the arrest was in fact staged, with its organizers misunderstanding an instruction "to get 3 SIMs". Further lending credence to the arrest being staged was footage of a note with a Russian phrase, which in fact read signature unclear. This was again interpreted as a misunderstood instruction, this time taken too literally. The FSB subsequently published a version of the footage with the Sims games blurred out.

Pseudo-operations: Pseudo-operations are those in which forces of one power disguise themselves as enemy forces. For example, a state power may disguise teams of operatives as insurgents and, with the aid of defectors, infiltrate insurgent areas. The aim of such pseudo-operations may be to gather short or long-term intelligence or to engage in active operations, in particular assassinations of important enemies. However, they usually involve both, as the risks of exposure rapidly increase with time and intelligence gathering eventually leads to violent confrontation. Pseudo-operations may be directed by military or police forces, or both. Police forces are usually best suited to intelligence tasks; however, military provide the structure needed to back up such pseudo-ops with military response forces. According to US military expert Lawrence Cline (2005), "the teams typically have been controlled by police services, but this largely was due to the weaknesses in the respective military intelligence systems."

The State Political Directorate (OGPU) of the Soviet Union set up such an operation from 1921 to 1926. During Operation Trust, they used loose networks of White Army supporters and extended them, creating the pseudo-"Monarchist Union of Central Russia" (MUCR) in order to help the OGPU identify real monarchists and anti-Bolsheviks.
An example of a successful assassination was United States Marine Sergeant Herman H. Hanneken leading a patrol of his Haitian Gendarmerie disguised as enemy guerrillas in 1919. The patrol successfully passed several enemy checkpoints in order to assassinate the guerilla leader Charlemagne Péralte near Grande-Rivière-du-Nord. Hanneken was awarded the Medal of Honor and was commissioned a Second Lieutenant for his deed.
During the Mau Mau uprising in the 1950s, captured Mau Mau members who switched sides and specially trained British troops initiated the pseudo-gang concept to successfully counter Mau Mau. In 1960, Frank Kitson, who was later involved in the Northern Irish conflict and is now a retired British general, published Gangs and Counter-gangs, an account of his experiences with the technique in Kenya. Information included how to counter gangs and measures of deception, including the use of defectors, which brought the issue a wider audience.
Another example of combined police and military oversight of pseudo-operations include the Selous Scouts in the former country Rhodesia (now Zimbabwe), governed by white minority rule until 1980. The Selous Scouts were formed at the beginning of Operation Hurricane, in November 1973, by Major (later Lieutenant Colonel) Ronald Reid-Daly. As with all Special Forces in Rhodesia, by 1977 they were controlled by COMOPS (Commander, Combined Operations) Commander Lieutenant General Peter Walls. The Selous Scouts were originally composed of 120 members, with all officers being white and the highest rank initially available for black soldiers being colour sergeant. They succeeded in turning approximately 800 insurgents who were then paid by Special Branch, ultimately reaching the number of 1,500 members. Engaging mainly in long-range reconnaissance and surveillance missions, they increasingly turned to offensive actions, including the attempted assassination of Zimbabwe People's Revolutionary Army leader Joshua Nkomo in Zambia. This mission was finally aborted by the Selous Scouts, and attempted again, unsuccessfully, by the Rhodesian Special Air Service.
Some offensive operations attracted international condemnation, in particular the Selous Scouts' raid on a Zimbabwe African National Liberation Army (ZANLA) camp at Nyadzonya Pungwe, Mozambique in August 1976. ZANLA was then led by Josiah Tongogara. Using Rhodesian trucks and armored cars disguised as Mozambique military vehicles, 84 scouts killed 1,284 people in the camp, registered as a refugee camp by the United Nations (UN). Even according to Reid-Daly, most of those killed were unarmed guerrillas standing in formation for a parade. The camp hospital was also set ablaze by the rounds fired by the Scouts, killing all patients. According to David Martin and Phyllis Johnson, who visited the camp shortly before the raid, it was only a refugee camp that did not host any guerrillas. It was staged for UN approval.
According to a 1978 study by the Directorate of Military Intelligence, 68% of all insurgent deaths inside Rhodesia could be attributed to the Selous Scouts, who were disbanded in 1980.
If the action is a police action, then these tactics would fall within the laws of the state initiating the pseudo, but if such actions are taken in a civil war or during a belligerent military occupation then those who participate in such actions would not be privileged belligerents. The principle of plausible deniability is usually applied for pseudo-teams. (See the above section Laws of war). Some false flag operations have been described by Lawrence E. Cline, a retired US Army intelligence officer, as pseudo-operations, or "the use of organized teams which are disguised as guerrilla groups for long- or short-term penetration of insurgent-controlled areas".
"Pseudo-operations should be distinguished," notes Cline, "from the more common police or intelligence infiltration of guerrilla or criminal organizations. In the latter case, infiltration is normally done by individuals. Pseudo teams, on the other hand, are formed as needed from organized units, usually military or paramilitary. The use of pseudo teams has been a hallmark of a number of foreign counterinsurgency campaigns."
Similar false flag tactics were also employed during the Algerian civil war, starting in the middle of 1994. Death squads composed of Département du Renseignement et de la Sécurité (DRS) security forces disguised themselves as Islamist terrorists and committed false flag terror attacks. Such groups included the Organisation of Young Free Algerians (OJAL) or the Secret Organisation for the Safeguard of the Algerian Republic (OSSRA). According to Roger Faligot and Pascal Kropp (1999), the OJAL was reminiscent of "the Organization of the French Algerian Resistance (ORAF), a group of counter-terrorists created in December 1956 by the Direction de la surveillance du territoire (Territorial Surveillance Directorate, or DST) whose mission was to carry out terrorist attacks with the aim of quashing any hopes of political compromise".