Troops from 16 different countries currently involved in Iraq
American military personnel are mainly deployed in seven military bases across Iraq: Ain al-Assad and Habbania in western Iraq; Ain Kawa and Dohuk in the Kurdistan region; al-Rustumia and al-Matar in Baghdad; and Qayyara in Nineveh province.
US forces, which number roughly 6,000 including 1,200 marines, share these bases with Iraqi regular forces. The majority are trainers, advisers and reconnaissance officers as well as analysts, but the personnel also include private security contractors bringing the total number to about 8,000 US personnel.
The US units include an artillery battalion in western Iraq and a squadron of Apache military helicopters tasked with defending Baghdad's Green Zone and the Baghdad international airport. This is not including more than 80 US fighter jets involved in operations in Iraq based in Turkey, Kuwait and US aircraft carriers in the Gulf.
The deployment is governed by a treaty with Baghdad ratified by the Iraqi parliament.
Up to 6,000 Iranian military personnel from the Revolutionary Guards and the Basij are thought to be present in Diyala, Salah al-Din, Waset, Babel and Baghdad provinces, embedded with the Popular Mobilisation Units.
Iranian troops take part in fighting on the ground. Between 2014 and September 2017, more than 100 Iranians have been killed including 23 high-ranking officers, mostly in Salah al-Din and Anbar.
The Iranian forces are equipped with tanks and APCs as well as mobile rocket launchers and surveillance drones.
The Iranians do not have permission from the Iraqi government or parliament to be present in the country. They are thought to have arrived following Islamic State's capture of Mosul.
Up to 350 British soldiers and advisers are deployed in Iraq, centred in Erbil and Nineveh. Their role is limited to training as well as logistical and aerial support for the Iraqi army and Kurdish Peshmerga forces.
Eight British Tornado fighters, a Type 45 destroyer and surveillance drones are also taking part in operations in Iraq. British military personnel are present as part of the international anti-IS coalition, sanctioned by Iraq's parliament and government.
Around 200 Australian special forces are present in the Kurdistan region, overseeing training, support and electronic surveillance of IS.
Six Australian F-18 jets are also involved in operations, through the anti-IS coalition.
Belgium deploys 120 soldiers and trainers in a camp near the Jordanian border with Iraq as well as in Kurdistan. They provide support and surveillance to anti-IS operations in northern Iraq.
Six Belgian F-16s and Fighting Falcon planes are also operating in the international coalition.
Up to 700 Canadian military personnel are present in Baghdad and Erbil, providing training, support and reconnaissance. Six FA-18 planes also operate as part of the international coalition
The Scandinavian nation has 140 military mostly non-combat personnel in advisory and training capacities. They are present in a small base shared with the Peshmerga southwest of Erbil.
Meanwhile, seven Danish F-16s operate over Iraq as part of the international coalition.
Around 500 French military personnel are present in Iraq as part of the special forces unit. Most of them are serving in a support capacity, including analysts working with images provided by fifteen French reconnaissance planes operating over Iraq and Syria.
The French personnel also track down French jihadists in the ranks of IS. They are part of the anti-IS coalition.
Berlin maintains 150 military personnel mostly officers, part of a newly formed European anti-terror unit, based between Baghdad and Erbil.
Germany also runs a training camp for Kurdish volunteers and fighters, with focus on programmes related to use of European weapons supplied to Iraq, mostly Kurdistan. Germany is part of the international coalition.
Rome dispatched 450 military personnel to Iraq amid warnings of the collapse of a dam in Mosul.
Fourt Italian Tornado jets also operate over Iraq. Italy is part of the coalition.
Around 150 Dutch soldiers are training Iraqi soldiers in northern Iraq.
Six F-16s and a Patriot missile battery are being operated in Iraq in support of the Peshmerga forces. Part of the international coalition.
Turkey has contributed nearly 600 troops, tasked with training Kurdish forces and Mosul tribes to fight IS and force it out of the city, as well as protecting borders from PKK infiltration.
It has weapons and armoured vehicles to defend its camp in Bashiqa, 30 kilometres northeast of Mosul.
There has been a lot of controversy about Turkish presence, which has been acknowledged by Kurdistan’s government, which confirmed it was officially requested by Baghdad.
This was denied by Baghdad, which asked Turkish troops to leave Iraq, with incitement from Russia and Iran, observers say.
Unconfirmed reports estimate around 200 Russian military personnel are present in Baghdad, in intelligence and liaison capacities. Iraqi airspace has been used by Russia to bomb targets in Syria.
Russia maintains an advanced radar facility north of Baghdad. Moscow obtained permission from the government but not parliament for the facility.
Forty advisers working with the army.
Unknown number of trainers in Baghdad.
A few dozen trainers working with the Iraqi army and local police in Baghdad and northern Iraq.
No heavy equipment or air cover. Part of the international coalition.