Philippines per the 1898 treaty Spain signed with the United States. However, no document was found to that effect. The Philippines then claimed the Spratly Islands in 1971 under President Marcos, after Taiwanese troops attacked and shot at a Philippine fishing boat on Itu Aba. Taiwan's garrison from 1946 to 1950 and 1956-now on Itu Aba represents an "effective occupation" of the Spratly Islands. China established a coastal defence system against Japanese pirates or smugglers. In 1958, China issued a declaration defining its territorial waters that encompassed the Spratly Islands. North Vietnam's prime minister, Phạm Văn Đồng, sent a formal note to Zhou Enlai, stating that the Government of the Democratic Republic of Vietnam (DRV) respected the Chinese decision regarding the limit of territorial waters. While accepting the 12-nmi principal with respect to territorial waters, the letter did not actually address the issue of defining actual territorial boundaries. North Vietnam recognised China's claims on the Paracels and Spratly Islands during the Vietnam War as it was being supported by China. Only after winning the war and conquering South Vietnam did North Vietnam retract its recognition and admitted it recognised them as part of China to receive aid from China in fighting the Americans. In 1987, China installed a small military structure on Fiery Cross Reef under the pretext of building an oceanic observation station and installing a tide gauge for the Global Sea Level Observing System. After a deadly skirmish with the Vietnamese Navy, China installed some military structures on more reefs in the vicinity of the Philippines and Vietnamese occupied islands and this led to escalating tensions between these countries and China over the status and ownership of reefs. In 1988, the Vietnamese and Chinese navies engaged in a skirmish in the area of Johnson South Reef (also called Gạc Ma Reef in Vietnam and Yongshu Reef in China). Under President Lee Teng-hui, Taiwan stated that "legally, historically, geographically, or in reality", all of the South China Sea and Spratly islands were Taiwan's territory and under Taiwanese sovereignty, and denounced actions undertaken there by Malaysia and the Philippines, in a statement on 13 July 1999 released by the foreign ministry of Taiwan. Taiwan and China's claims "mirror" each other; during international talks involving the Spratly islands, China and Taiwan have cooperated with each other since both have the same claims. It was unclear whether France continued its claim to