The United States-led coalition to fight the Islamic State militant group continues to grow, with numerous nations providing varying levels of backing in the form of military equipment, aid and political support. It is unclear, however, what exactly constitutes being a member of this coalition and how many nations have signed up.

In his speech to the United Nations on Wednesday morning, President Obama said, “Already, over 40 nations have offered to join this coalition.”

But on Tuesday, Secretary of State John Kerry said more than 50 nations have agreed to join the coalition. And in a document released by the State Department on Tuesday, 62 nations (including the European Union and the Arab League) are listed as providing support to the U.S.-led coalition.

The strongest allies in the coalition are those providing air support to the United States, while others are offering delivery services and some are providing humanitarian aid.

These are the allies listed by the State Department as aiding the “international effort to counter ISIL, support the people of Iraq and Syria, and mitigate the Humanitarian consequences of the conflict in Iraq and Syria”:

Allies providing air support, and military equipment

Iraq: Location of the fighting. Authorized France to use Iraqi air space and has welcomed the support from Obama and other members of the coalition in their fight against the Islamic State. The Iraqi government requested military airstrikes from the United States to help combat the Islamic State.

Jordan: Destroyed a number of Islamic State targets through air strikes in Syria. Jordan has also worked to cut off funding to extremist and terrorist organizations.

Bahrain: Carried out air strikes against the Islamic State in Syria in tandem with allies.

Saudi Arabia: Participated in air strikes in Syria. Saudi Arabia has frequently condemned the Islamic State and has donated $100 million to the United Nations Counter-Terrorism Center and $500 million in humanitarian assistance.

United Arab Emirates: Participated in air strikes in Syria. The UAE has joined together with other Gulf nations to condemn the Islamic State and offer support to the coalition.

France: Bombed a warehouse occupied by the Islamic State in Iraq last week. One of the United States’ key allies in the air, the French Air Force has also carried out recon flights over Iraq and has vowed to take part in future airstrikes “if needed.” To date, France has sent 59 tons of humanitarian cargo to Irbil with further deliveries due soon. The French have insisted the group should not be referred to as the “Islamic State.”

The French military released cockpit video of Rafale jets participating in their first air strikes in Iraq as part of the country's promise to join military action against the Islamic State. (Reuters)

Germany: Has sent 40 paratroopers to Iraq to provide weapons training to Kurdish fighters. Germany is also sending 16,000 assault rifles, hundreds of anti-tank weapons and armored vehicles. Some Kurdish fighters are also being trained in South Germany. They will provide enough weapons to arm 4,000 Kurdish soldiers as well as 36 tons of humanitarian aid.

Germany sent on Thursday its first arms shipment to northern Iraq to help Kurdish Peshmergas and Iraqi soldiers fight Islamic State militants who have taken over swathes of Iraq. (Reuters)

Canada: Has deployed “several dozen members” of the Canadian Armed Forces to Iraq. The Canadian Air Force also provided airlift support to Albania last week, delivering 503,000 pounds of military supplies to Iraq. Canada has sent $15 million to support security measures in the region — including $10 million of “non-lethal” assistance and $5 million of humanitarian aid.

United Kingdom: Supplied arms to the Kurds and a Royal Air Force squadron has contributed to surveillance operations. Gifted $1.6 million of weapons and ammunition. Prime Minister David Cameron has not ruled out contributing to U.S.-led airstrikes in the future. Some $38 million has been committed to aid.

Australia: Has agreed to deploy a “military force to the region” and will play a part in U.S.-led airstrikes. Australian Special Forces are advising Iraqi forces. Provided $5 million in humanitarian aid to Iraq as well as aircraft, early warning systems and military stores. Prime Minister Tony Abbott has backed Obama’s position, describing the Islamic State as a “death cult.”

Italy: Sent $2.5 million of weaponry, including machine guns, rocket-propelled grenades and a million rounds of ammunition, as well as humanitarian aid. Italy has no plans at present to take part in airstrikes but has offered to aid in the refueling of planes instead.

Czech Republic: Provided fighter jets and 500 tons of ammunition to the Iraqi army, delivered by the Canadian Air Force. Also contributed $1.5 million in humanitarian aid to victims of the Syrian conflict.

Albania: Provided weapons and ammunition to Kurdish forces, with the first shipment sent on Sunday. Earlier this month, Albania said it would provide up to 22 million rifle rounds, 32,000 artillery shells to Kurdish forces as well as 10,000 automatic rifles to Afghanistan.

Netherlands: Provided 1,000 helmets and 1,000 bulletproof vests for Kurdish forces, as well as $10 million in humanitarian aid. The government said Wednesday that it would send six F-16 fighter jets to strike the Islamic State in Iraq.

Estonia: Provided a million machine gun cartridges and a Hercules transport aircraft as well as $90,000 to support displaced Iraqis.

Hungary: Provided 7 million cartridges and “thousands” of mines and armor-piercing shells. Hungary has sent a $90,000 aid package to Christians in Irbil.

Turkey: President Tayyip Erdogan has said he will “give the necessary support to the operation. The support could be military or logistics.” Moe than 100 trucks of humanitarian aid has been sent to Turkmen in Northern Iraq since June, totaling $1.9 million so far. Turkey has also funded the construction of a camp for 20,000 Iraqi Turkmen.

Belgium: The Ministry of Foreign Affairs has said “we are positively inclined to contribute” and “we have the military capacity to do so. Belgium does have an interest to contribute.” Belgium has sent 13 tons of aid to Iraq.

Denmark: Provided a transport aircraft to support the international efforts.

Lebanon: The state will not send troops or weapons but will “receive military help to fight the organization through the Army” according to its foreign minister.

Allies providing humanitarian aid

Sweden: Donated $13 million of aid to Iraq in 2014 to date.

Kuwait: Donated $9.5 million to the United Nations for aid in Iraq.

Switzerland: Donated $9 million in aid to Iraq in 2014 so far.

Japan: Granted $6 million in emergency aid to help displaced people in Northern Iraq.

Austria: Provided $1.3 million in emergency aid to Iraq.

New Zealand: Donated $1 million in humanitarian aid.

Republic of Korea: Provided$1 million in humanitarian aid to help displaced persons in Iraq.

Ireland: Provided $300,000 to UNICEF, a further $300,000 to the Red Cross and $850,000 this year to Iraq in the form of aid.

Spain: Supported United Nations Human Rights Council resolution and donated $640,000 in humanitarian aid.

Slovakia: Donated $25,000 to assist soldiers in the Kurdish region of Iraq.

Norway: Contributed to the most recent UNESCO aid drop, including 40,000 blankets, 10,000 kitchen sets and 18,000 plastic tarpaulins.

Luxembourg: Supported United Nations Resolution 2170 and will step up humanitarian assistance for the Iraqi people. Contributed to aid deliveries from the United Nations.

Qatar: Passed a new law to stop charities diverting money towards the Islamic State. Sent six aircraft carrying 300 tons of humanitarian aid to Iraq.

Allies who have expressed support

Bulgaria: Foreign minister has said the conflict “poses a direct threat to Bulgaria” but has not offered any military or aid distance so far.

Egypt: Released a statement strongly denouncing the execution of American journalist James Foley, with a spokesman calling for the “international community to rally efforts to fight terrorism.”

Finland: Minister for Foreign Affairs said his country will “concentrate on delivering humanitarian aid to people in desperate need”

Georgia: In a statement, its defense minister said officials “fully support what the United States i doing to eradicate these barbarians”.

Greece: In a statement, the government condemned the actions of the Islamic State and said “we express our solidarity with the Iraqi government.”

Israel: Prime Minister Benjamin Netanyahu said in a statement “these groups must be fought, they must be rolled back, and they must ultimately be defeated. That’s why Israel fully supports President Obama’s call for united action against ISIS.”

Kosovo: In a Facebook statement, Prime Minister Hashim Thaci said it will help the United States to destroy ISIS and Kosovo is part of the “emerging global alliance to fight a great evil”.

Oman: The Sultan of Oman has said “no one can afford to neglect a situation as serious as this” and his government will work “as fast as possible to end IS threat.”

Poland: Intends to politically support the fight, as well as through NATO membership, but does not envisage soldiers participating in military operations.

Croatia: Committed to “helping provide Kurdish forces urgently needed arms and equipment.”

Romania: In a statement, the Romanian Ministry of Foreign Affairs said it will “contribute to the international community efforts to combat international terrorism and the ISIL phenomenon.”

Singapore: Ministry of Foreign Affairs has cited a “critical need for the international community to work closely together to counter this treat.”

Taiwan: In a statement, the Ministry of Foreign Affairs said it would “monitor the threat to global security” and will “cooperate closely with the international community to provide humanitarian aid to the victims of ISIL attacks.”

Coalition supporters

The following nations have an unspecified commitment but State Department has said they are part of the coalition: Andorra, Bosnia, Lithuania, Macedonia, Malta, Mexico, Moldova, Morocco, Portugal, Serbia, Slovenia, Tunisia and Ukraine.

Non-nation supporters

There are two other bodies that have backed the coalition but are not nation states:

Arab League: Released several statements urging its members to confront the Islamic State “militarily and politically.” Foreign ministers from all of the member states have agreed to take “all necessary measures to confront the Islamic State.”

European Union: The EU Civil Protection Mechanism has been activated to support “rapid deployment of in-kind assistance and expertise to Iraq.” Ten member states are providing essential relief through a “humanitarian air bridge.” The European Commission has increased the level of aid to $22 million in 2014.