The Japanese occupation of the Malayan region during World War II weakened British influence there and unleashed anti-colonial, Malayan nationalism. With the help of the Chinese, the Malayan Communist Party grew stronger, fought the Japanese occupation, and threatened British interests. In response, the British established the multi-ethnic Federation of Malaya in 1948 as a part of a wider anti-communist plan. In 1963, "Malaya" became "Malaysia" with the acquisition of what territories?