On January 18, 1813, the Americans forced the retreat of the British and their Native American allies from Frenchtown, which they had earlier occupied, in a relatively minor skirmish. The movement was part of a larger United States plan to advance north and retake Fort Detroit, following its loss in the Siege of Detroit the previous summer. Despite this initial success, the British and Native Americans rallied and launched a surprise counterattack four days later on January 22. Ill-prepared, the Americans lost 397 soldiers in this second battle, while 547 were taken prisoner. Dozens of wounded prisoners were murdered the next day in a massacre by the Native Americans. More prisoners were killed if they could not keep up on the forced march to Fort Malden. This was the deadliest conflict recorded on Michigan soil, and the casualties included the highest number of Americans killed in a single battle during the War of 1812.