From the sandy beaches of Thitu Island, blue waters stretch for as far as the eye can see. It feels like a tranquil paradise: there’s no noisy road traffic, air pollution or crowds. But Thitu is not a luxury retreat, it’s a tiny island in the remote Spratly chain and one of the world’s most fiercely contested maritime sites.

Thitu has been occupied by the Philippines since 1974 and is home to 387 civilians. However, China also claims the island and much of the surrounding South China Sea. Thitu and its people are on the frontline of an intensifying struggle against their superpower neighbour.

As is the case for many other features in the South China Sea, even the name of the island is controversial. The Philippines calls it Pag-asa Island (meaning “hope” in Tagalog), while the other claimants, China, Vietnam and Taiwan, use separate names. The name Thitu is used by international courts.

“We will not leave the island, no matter what happens,” says Larry Hugo, the head of the fisherfolk association on Thitu. Over the years he has been chased by Chinese vessels and has seen the number of Chinese boats plying the waters off Thitu grow in number, joined by aircraft and even drones overhead, he says. “It seems like Pag-asa is under surveillance. They are watching over what residents of Pag-asa Island are doing. They are more now than before.”

Residents have lived with the threat of China for years, but recently tensions in the South China Sea have escalated. Earlier this year, Chinese vessels in effect imposed a blockade to stop Philippine resupply missions from reaching troops based at Second Thomas Shoal, which lies 121 nautical miles away from Thitu, with the Philippines repeatedly accusing China of ramming its boats and blasting them with water cannon.

This month, two Filipino coastguard ships were damaged in a collision with Chinese vessels at another site, Sabina Shoal, in the first such incident there in recent memory. Both Sabina and Second Thomas fall within the Philippines’ exclusive economic zone (EEZ). Thitu does not.

On Friday, Chinese state media drew attention to Thitu, saying the Philippines could “stir up trouble” through its presence on the island and accusing Manila of “illegally” occupying it and expanding military infrastructure. Then on Sunday, Philippines and Chinese vessels clashed near Sabina Shoal over what Manila said was a resupply mission for fishers, and what China’s coast guard termed an “illegal” entry into its waters.

China also introduced new regulations in June that empower its coastguard to detain foreigners accused of so-called trespassing. Thitu’s fishers now go out only in larger groups, says Hugo. “We discussed that if one of us is arrested, all of us will join,” he says.