The U.S. Navy's first two advanced P 8APoseidon patrol aircraft have arrived in Japan, U.S. military officials said onMonday, helping to upgrade America's ability to hunt submarines and othervessels in seas close to China as tension in the region mounts.

日本防卫省上月底透露，美军将在冲绳县嘉手纳基地部署6架P-8A“波塞顿”海上反潜巡逻机。据英国媒体报道，美国国防部12月2日表示，首批2架飞机现已部署到位，这将进一步提升美国海军在东海地区的反潜作战能力。

The initial deployment - another four of theaircraft are due to arrive in the coming days - was planned before China lastmonth established an air defense identification zone covering islandscontrolled by Japan and claimed by Beijing.

“P-8A是目前世界上最先进的远程反潜和反水面作战飞机。”美国国防部发言人杰弗里·普尔称，首批2架P-8A反潜巡逻机已在本月1日抵达日本冲绳县嘉手纳基地，预计其余4架会在本周晚些时候到位。

The Pentagon says it is routinely flyingoperations in the region, including in China's newly declared air defense zone,without informing Beijing ahead of time.

P-8A“波塞顿”海上反潜巡逻机，是美国波音公司在737客机的基础上升级改造而成，用于替代已服役近50年的P-3“奥利安”巡逻机。P-8A反潜巡逻机上装备有最先进的雷达设备以及鱼雷和反舰导弹，相较于P-3巡逻机，其飞行距离和执行任务时间均大为增加。

One U.S. defense official, speaking oncondition of anonymity, told Reuters these routine operations includesurveillance flights.

美国国防部称，这6架P-8A反潜巡逻机将在嘉手纳基地所处的东海地区执行常规飞行任务。据一位美国国防部官员透露，这些常规飞行任务包括在东海地区进行监察飞行。

The deployment of the P8As came before U.S.Vice President Joe Biden left for Asia this week, where he is seeking to strikea balance between calming military tensions with China and supporting Japan asit wrangles with Beijing over the islands.

Equipped with the latest radar equipment andarmed with torpedoes and antiship missiles, the P8A is able to fly furtherand stay out on a mission longer than the P-3.

"The P-8A is the most advancedlong-range anti-submarine and antisurface warfare aircraft in the world,"the Pentagon said.

Lieutenant Colonel Jeffrey Pool, a Pentagonspokesman, said the first two P-8As arrived in Japan on Sunday. The other fourwere expected to arrive there later this week, a Navy spokeswoman said.

     11月23日，中国宣布划设东海防空识别区。由于东海识别区覆盖钓鱼岛及其附属岛屿海域，日美等国反应强烈，致使东海局势趋紧。

One U.S. official, speaking on condition ofanonymity, acknowledged the deployment came at a moment of region tensions. Theofficial said the timing was a coincidence, but one that would bolster the U.S.military's efforts to monitor the maritime environment in the region.

That includes the area around the disputedislands, known to the Japanese as the Senkakus and to the Chinese as theDaioyu, the official said.

英国路透社指出，美国副总统约翰·拜登本周访亚，寻求找到缓和东海紧张局势的切入点和平衡点，而美军选择此时在该地区部署最先进的反潜巡逻机，或许还有其他含义。

Washington takes no position on thesovereignty of the islands. However, it recognizes Tokyo's administrativecontrol and says the U.S.-Japan security pact applies to them, a stance thatcould drag the United States into a military conflict it would prefer to avoid.

一位美国政府官员也承认，美方的确是在一个地区局势紧张的“非常时刻”作出部署安排，“尽管是碰巧选择了这个时间点，但这一巧合却能极大提升美军对东海地区海事环境的监控能力”。