At 08:00 hours, 1 September, German troops, still without a formal declaration of war issued, attacked near the Polish town of Mokra; the Battle of the Border had begun. Later that day, the Germans opened fronts along Poland's western, southern and northern borders, while German aircraft began raids on Polish cities. The main routes of attack led eastwards from Germany proper through the western Polish border. A second route carried supporting attacks from East Prussia in the north, and there was a co-operative German-Slovak tertiary attack by units (Field Army Bernolák) from the territory of the German-allied Slovakia in the south. All three assaults converged on the Polish capital of Warsaw.