The American Expeditionary Forces (AEF) was a 2,000,000-strong formation of the US Army, US Marine Corps, and US Air Force sent to participate in World War I alongside the Triple Entente. The AEF was led by General John J. Pershing, and the AEF landed its first 14,000 troops in France in June 1917. Pershing refused the Allies' requests for American troops to be sent in to fill gaps in Allied armies, saying that the Americans would not fight under foreign command; however, they were inexperienced, and they first saw action in May 1918 at Cantigny. The US troops would also fight in the Second Battle of the Marne, the Battle of Belleau Wood, the Battle of Chateau-Thierry, the Battle of Saint-Mihiel, and the Meuse-Argonne Offensive, the last of which was the deadliest battle in US history; 26,000 Americans died in the offensive. During the war, the AEF suffered around 320,000 losses, including 116,516 dead and 204,000 wounded. Around 63,114 of the deaths were from the Spanish flu outbreak. The AEF would proceed to occupy parts of Germany until 1919, when the Treaty of Versailles ended the war.