The Philippines and Vietnam are forging closer ties in a symbolic move after China stepped up activities in disputed areas of the East Sea -- the Vietnamese term for the South China Sea, raising tension in the potential flashpoint.
China claims almost the entire East Sea, believed to be rich in oil and gas deposits and fishery resources. Brunei, Malaysia, the Philippines, Vietnam and Taiwan also claim parts of the sea, crossed by ships carrying $5 trillion a year in cargo.
Pham Binh Minh, Hanoi's deputy prime minister and foreign minister, on Thursday began a day-two visit to Manila for talks to build a strategic partnership and strengthen security, trade and cultural ties.
"We believe a strategic partnership enhances the cooperation on a comprehensive basis," Foreign Minister Albert del Rosario said, adding that the strategic partnership with Vietnam would be Manila's third, after the United States and Japan.
Although officials stopped short of saying the new effort was designed to fend off China, the Philippines and Vietnam have been growing steadily closer in the face of China's growing assertiveness in the region.
The strategic partnership will step up high-level contacts between the two militaries, through joint naval patrols, training and exercises.
Beijing has started construction work on six reefs it occupies in the Spratlys to expand the territories, building ports, an airfield and communications and surveillance facilities. It has also deployed more navy and coastguard ships.
"The massive reclamation is a threat to all of us," Del Rosario said, adding it has fed tension.
China's assertiveness is leading to closer cooperation among its neighbors, in some cases, erasing old distrust.
In December, Vietnam supported the Philippines in its arbitration case against China at the U.N. tribunal in the Hague. China has refused to participate. The Philippines expects a ruling early next year.
Last year, Vietnam and the Philippines held their first naval talks and their seamen played volleyball and soccer on a Vietnamese-held island, and Vietnam's two most powerful frigates made port calls in Manila.
"We already have joint training and exercises with the U.S. military every year and we are looking forward to hold exercises with the Vietnamese navy," a Philippine navy officer told Reuters.