In August 1914, World War I began when alliance obligations arising from the war between Serbia and Austria-Hungary brought Germany and Russia to war, while Germany's invasion of Belgium directly triggered Britain's entry. After a series of military events and political intrigues, Russia declared war on Turkey in November. Turkey then joined the Central Powers in fighting the Entente Powers. In response to the war with Russia and Britain, and further motivated by its alliance with Turkey, Germany accelerated its plans to weaken its enemies by targeting their colonial empires, including Russia in Turkestan and Britain in India, using political agitation.