The Fengtian clique's support from abroad was Japan, which had vested economic and political interests in the region dating from the end of the Russo-Japanese War and was interested in exploiting their region's largely-untapped natural resources. The Japanese Kwantung Army, based in the Kwantung Leased Territory, also had responsibility for safeguarding the South Manchurian Railway and so had troops stationed in Manchuria, providing material and logistical support for the Fengtian clique. The co-operation initially worked to the benefit of both parties. Zhang provided security for the railroad and Japanese economic interests, suppressing Manchuria's endemic banditry problem and allowing extensive Japanese investments. The Imperial Japanese Army assisted Zhang in the two Zhili-Fengtian Wars, including the suppression of the anti-Fengtian uprising by General Guo Songling, a senior Fengtian clique leader. However, Zhang wanted Japan's aid only to consolidate and expand his territory, but Japan envisioned a future joint occupation of Manchuria with Zhang. After he had achieved his objectives, he tried to improve relations with the United States and the United Kingdom bu allowing both countries open access to the trade, investment and economic opportunities in Manchuria that he had allowed only to the Japanese.