THITU ISLAND, SOUTH CHINA SEA (AFP) - Philippine military chief General Gregorio Catapang looks worried as he surveys the rusted cranes and eroded runway on the tiny island of Thitu, now on the front line of a rapidly intensifying construction war in the South China Sea.
Fewer than 48 kilometres away, China's giant construction cranes glint on the horizon, a sign of the Asian giant's reef-building frenzy in the disputed Spratly chain that has seen new islands appear seemingly overnight.
As China and fellow rival claimant Vietnam race to pave over reefs and build structures in the strategically important sea, the Philippines stands out as a laggard.
The 356 residents of the remote Manila-held coral outcrop of Thitu fear they will soon be forced out by China's aggressive land grab, in a conflict fought, so far, with dredgers and cement.
"Before we landed we saw the reclamation in the (nearby) Subi Reef and it's really enormous," Catapang said on a tour of the island's largely decrepit facilities. An old navy transport ship lay half-submerged in waters off the coast, with two anti-aircraft guns the only visible defences.
China claims nearly all of the South China Sea, even waters approaching the coasts of its Asian neighbours, and in recent years it has caused alarm with increasingly aggressive actions to assert its claims and increase its presence.
The Spratlys, an archipelago of more than a hundred islands, reefs and atolls between Vietnam and the Philippines, is one of the most hotly contested areas because of its strategic military importance.
The United States last week sounded the alarm, accusing China of building up to 800 hectares (2,000 acres) of artificial islands in the Spratlys, and warning it could construct airfields, surveillance systems and harbours that would jeopardise regional stability.
Alarmed at the Chinese activity, other Spratlys claimants have not been idle. Vietnam is reported to be reclaiming land in two areas, while Taiwan and Malaysia have announced plans to improve their naval facilities.
The Philippines, which occupies nine islands or reefs in the chain, in contrast has done very little - partly because of funding constraints, but also because it is pinning its hopes on having the United Nations mediate the dispute.
'Without firing a shot'
Life is usually uneventful for the inhabitants of Thitu, the largest Philippine-occupied island which lies 433 kilometres from the major Philippine island of Palawan, and receives electricity just five hours a day.
They include soldiers, coastguard personnel and military-employed civilians, many of whom bring their wives and children with them to stave off loneliness.
But the Philippine army says that since last month Chinese vessels off the Subi reef have warned Filipino air force planes flying in and out of Thitu to leave, saying they are violating its military airspace.
"This is bad for us who live here. We depend on the planes to deliver our food," one concerned municipal employee, 37-year-old Larry Jugo, told AFP.
Rear Admiral Alexander Lopez, commander of Philippine forces in the South China Sea, said the action was effectively an enforcement of an undeclared air defence identification zone.
"They build these things, they say for legal reasons, but for military purposes as necessary. That's very alarming," he said.
Elsewhere in the Spratlys, Lopez said China has also been harassing Filipino vessels supplying marines on Second Thomas Shoal. The puny unit of nine men lives on a rusting navy ship that had been deliberately grounded on a reef.
China has also been driving away Filipino fishermen at the Scarborough Shoal, 595 kilometres to the northeast of the Spratlys and within the Philippines' exclusive economic zone but which China has controlled since 2012.
Philippine authorities and regional analysts see it as an powerful campaign aimed at making it impossible for the Philippines to hold on to its claims.
"As far as I know, there is not much that the Philippines can do," even if it wins its UN case, said Harry Sa, an American research analyst for the Singapore-based S. Rajaratnam School of International Studies.
"I think China is doing something smart: It is gaining territory without firing a single shot."
'We have nowhere to run'
Outgunned by China's military might, the Philippines' strongest card has been a suit to a United Nations tribunal, asking it to rule that China's claims are illegal.
A verdict is expected next year, but Beijing has refused to participate and would reject any finding against it.
Analysts say China is unlikely to deliberately fire at Filipino vessels, wary the Philippines could ask the United States to retaliate by invoking a 1951 mutual defence treaty, and also reluctant to be seen as a regional aggressor.
Nonetheless, the Philippines has sought to upgrade its capabilities by acquiring two second-hand US patrol craft and ordering fighter jets from South Korea that would allow it to manoeuvre more swiftly over the contested waters.
But its efforts to draw in the United States, its closest ally and former colonial ruler, have stumbled, mainly because a 2014 treaty to allow American forces to use Filipino bases and build facilities is in legal limbo.
With the Philippines becoming increasingly vulnerable, Thitu islander Jugo plans to send his wife and two children home to Palawan next year just in case trouble erupts.
"We have nowhere to run... we will be forced to fight whatever happens," he said.