Immediately after its creation at the 1964 Arab League summit in Alexandria, the PLO was effectively under the control of the Arab states, especially Nasser's Egypt. The Palestinians would not gain independent control of the organization until Yasser Arafat's Fatah faction wrested it from Nasser-backed Palestinians in 1968–69, when the Arab states were discredited by losing the Six-Day War, and militant Palestinian organizations were rapidly gaining in importance. The PLA was originally organized into three brigades, named after historic battles:
Ayn Jalut, based in Gaza, then administered by Egypt.
Qadisiyyah, originally based in Iraq, but transferred to Jordan in 1967.
Hattin, based in Syria.
These brigades were staffed by Palestinian refugees under the control of the host countries, who would perform their military service in these units instead of in their host countries' regular armed forces. Formally, the PLA was under the command of the PLO's Military Department, but in practice, none of the governments involved relinquished control of the brigades. In 1968, the Popular Liberation Forces, better known as the "Yarmouk Brigade", were established within the framework of the PLA to perform commando actions against Israeli forces in the Gaza Strip, occupied by Israeli forces the year before. Generally the PLA refrained from this kind of underground action, having been built up as something of a conventional military parade showpiece. At its largest, the PLA comprised eight brigades with a total of some 12,000 uniformed soldiers. They were equipped with small-arms, mortars, rocket launchers, wheeled BTR-152armored personnel carriers and T-34/85 tanks. However, the PLA was never deployed in the form of a single fighting unit for the PLO, but instead battalion-size elements were utilized as an auxiliary force by its controller governments.
After its foundation, the PLA came to be used as political cover by its host governments, especially Syria. In course of the Black September of 1970, hastily repainted Syrian Army tanks under the command of the PLA were sent into Jordan to aid the Palestinian guerrillas against the Jordanian Armed Forces, probably with the ultimate aim to overthrow the Jordanian monarchy. Although the initial invasion was successful, with PLA forces capturing Irbid and declaring it a "liberated" city, the Jordanian military eventually managed to stall the attack in course of heavy fighting. After international pressure, and threats of intervention from both Israel and the United States, the combined PLA-Syrian forces were forced to turn back; an embarrassment which would contribute greatly to the overthrow of the government of Salah Jadid by Hafez al-Assad. The failure of the invasion has also attributed to the fact that the Syrian Air Force under al-Assad had refused to enter the fighting in the first place. During the Lebanese Civil War, Syria likewise made extensive use of the PLA as a proxy force, including against the PLO. The PLA was largely destroyed as a fighting force during the 1982 Israeli invasion of southern Lebanon that started the 1982 Lebanon War. Its fighters in Lebanon left for Tunis when the PLO evacuated Beirut that year, in a US-sponsored cease fire agreement. The Egyptian PLA was also deployed in Lebanon in 1976, after Palestinian leader Yassir Arafat had approached the Egyptian presidentAnwar Sadat, to mend relations damaged by Sadat's peacemaking attempts with Israel. Still, the Egyptian units never proved as important as the fully deployed Syrian PLA. Many PLA soldiers in Egypt and Jordan later became the core of the Palestinian Authority's National Guard, after the signing of the 1993 Oslo Accords, when they were allowed to enter the Palestinian Territories to take up positions in the PNA security services.
The Syrian PLA remains active, closely coordinated with the Syrian-controlled as-Sa'iqa faction of the PLO, although the importance of both had diminished over the years. The PLA has been rebuilt and Palestinians in Syria are still drafted to perform their military service in its ranks. Though completely staffed by Palestinians, it remains outside of the PLO's control, and is in effect integrated into the Syrian Army. Nevertheless, it poses as an independent entity, and occasionally organizes pro-government rallies celebrating Syrian commitment to the Palestinian cause. With the outbreak of the Syrian Civil War, the PLA sided with the government and began to fight against the Syrian opposition. Led by Major General Muhammad Tariq al-Khadra, the PLA has taken part in campaigns in the Rif Dimashq, Daraa, and Quneitra Governorates. In early 2015, several PLA officers and fighters were reportedly executed for refusing to fight against rebels in Daraa. Around 228 PLA fighters have been killed in action by September 2017; one of the highest ranking fatalities being a brigadier general, Anwar al-Saqa.
