Preoccupied with internal problems, France paid little attention to foreign policy in the period between late 1912 and mid-1914, although it did extend military service to three years from two over strong Socialist objections in 1913. The rapidly escalating Balkan crisis of July 1914 surprised France, and not much attention was given to conditions that led to the outbreak of World War I. Paris was caught by surprise when the German army suddenly invaded and plunged toward Paris. However London decided that France must be rescued or Germanyh would be far too powerful, and so it declared war on Germany.