US and Japanese officers are discussing worst-case contingency plans for retaking the disputed Diaoyu Islands if China moves to seize them, US officials said.
Japan's Nikkei newspaper first reported the talks, which prompted a strong reaction from Beijing. "We have contingency plans and we discuss them with allies," a US official said on condition of anonymity.
He said it was "natural" that the two governments would confer on emergency scenarios given recent tensions.
A Pentagon official also confirmed the Nikkei report. But both sources said the US government did not want to fuel tensions, and that the contingency planning would be only one of many topics on the agenda at a meeting between top US and Japanese officers in Hawaii scheduled for yesterday.
Officially, the Pentagon would neither confirm nor deny whether the contingency plans were under discussion.
Lieutenant Colonel Catherine Wilkinson, using the Japanese name for the islands, said: "As a matter of policy, we do not discuss our military planning efforts. The US policy on the Senkaku Islands is long-standing. We encourage the claimants to resolve the issue through peaceful means." The US has made clear that its alliance with Tokyo applies to the islands, raising the possibility of US military action in support of Japan if China moves to seize them.
The dispute has escalated in recent months, with Beijing repeatedly sending ships to waters around the islands to back up its sovereignty claims. Tokyo has alleged that a Chinese frigate locked its radar on a Japanese destroyer in January.
China's defence ministry said in response to the Nikkei report: "The determination and will of Chinese military forces to safeguard China's sovereignty and territorial integrity are steadfast.
"We firmly oppose any action that could further complicate and magnify the situation."