AFP, TOKYO:  Japan warned China yesterday that its extensive land reclamation in the disputed South China Sea does not make ownership "a done deal", after Beijing announced it had almost finished its controversial island-building.
The rebuke came after Washington urged China against militarisation of the area, saying that risked escalating tensions, even as satellite pictures have shown a runway long enough to let even the biggest aircraft land.
It also came as details emerged of a joint exercise between Japan and the Philippines, as the relationship blossoms between the two regional powers most prepared to push back against Beijing's perceived rising aggression.
"We hold serious and significant concerns about the unilateral actions aimed at changing the status quo, which are bound to increase tension," Japan's Chief Cabinet Secretary Yoshihide Suga told reporters.
"With the completion of the reclamation, we must not accept the land reclamation as a done deal. We demand (China) not take unilateral actions that bring irreversible and physical changes," he said.
Japan has long criticised China's attempts to change the status quo unilaterally and by force, mindful of its own dispute with Beijing over islands in the East China Sea.
The US says China has created 2,000 acres (800 hectares) of new land in the South China Sea in the last 18 months.
Huge dredgers have been spotted dumping sand on previously submerged reefs, many of which now house buildings and ports.