On June 17, with tensions increasing, naval "Rikusentai" from Japanese ships had joined British, Russian, and German sailors to seize the Dagu forts near Tianjin. Four days later, the Qing court declared war on the foreign powers. The British, in light of the precarious situation, were compelled to ask Japan for additional reinforcements, as the Japanese had the only readily available forces in the region. Britain at the time was heavily engaged in the Boer War, and, consequently, a large part of the British army was tied down in South Africa. Deploying large numbers of troops from British garrisons in India would take too much time and weaken internal security there. Overriding personal doubts, Foreign Minister Aoki Shūzō calculated that the advantages of participating in an allied coalition were too attractive to ignore. Prime Minister Yamagata likewise concurred, but others in the cabinet demanded that there be guarantees from the British in return for the risks and costs of a major deployment of Japanese troops. On July 6, the 5th Infantry Division was alerted for possible deployment to China, but without a timetable being set. Two days later, on July 8, with more ground troops urgently needed to lift the siege of the foreign legations at Peking, the British ambassador offered the Japanese government one million British pounds in exchange for Japanese participation.