U.S. and Filipino Marines
U.S. and Filipino Marines wade ashore in mock exercises to retake a small island. Reuters

Military activity in East Asia is increasing amid new flare-ups of regional territorial disputes. Complicated conflicts over ownership of maritime zones and interpretations of sovereign rights are again threatening to destabilize a region rife with rising nationalistic sentiments and expanding militaries.

In Northeast Asia, Chinese and Russian ships left the Chinese port of Qingdao on Thursday to initiate exercises in the Yellow Sea, where China's first aircraft carrier is already drawing attention. The exercises are occurring as relations between China and Japan relations suffer again from a dispute over the islands called Senkaku by the Japanese and Diaoyu by the Chinese.

The leader of Japan's opposition Liberal Democratic Party visited the Yasukuni Shrine on Wednesday, sparking new bursts of resentment and upset in China. The shrine honors Japan's war dead -- including war criminals -- from past conflicts and is seen by both China and Korea as a symbol of Tokyo's past military aggression. In addition, the governor of Tokyo, nationalist Shintaro Ishihara, created further backlash last week with statements expressing his municipal government's intention to purchase the islands, drawing new condemnations from China.

Russia and Japan have their own disputes over the Kurile Islands, lying between Japan's northern Hokkaido Island and Russia's Sakhalin Island, which were seized by the Soviet Union at the end of World War II. Their relations have increasingly soured in past years as Russia resumed flying its strategic bombers off its Pacific coast, an activity that had been suspended after the collapse of the Soviet Union.

Meanwhile, in Southeast Asia, the U.S. is engaging in new naval exercises with other countries in the region even as new conflicts emerge over multinational disputes in the South China Sea.

China and the Philippines have faced off for the past three weeks over the Scarborough Shoal, located to the northeast of the South China Sea, approximately 220 kilometers or 120 nautical miles west of the Philippines' main island of Luzon. The Filipino press reported that China withdrew two vessels on Monday. However, the Filipino navy may deploy more forces to the area, and Chinese media are reporting that at least one of their nuclear-powered submarines left a major South China Sea naval base. The Filipino government urged other states in the region to take a stand with it against China on Monday.

Vietnam voiced its position on Tuesday, stating that China's intentions in the South China Sea seriously violate Vietnam's sovereignty. Both China and Vietnam claim the Paracel and Spratly Islands, which lie in the northwestern and southern areas of the South China Sea. China controls the former island group, which it calls the Xisha Islands, and Vietnam labels the Hoang Sa Islands. China fought Vietnam to gain control over the Paracels in 1974. The two nations engaged in a brutal border war in 1979, which killed tens of thousands. Until the late 1980s, they have skirmished on and off in the Paracels, along their mutual land border, and even on one occasion in the Spratly Islands in 1988.

The Spratlies are comprised of more than 750 reefs, atolls, rocks and islets -- many of which do not qualify as true islands, are submerged, and have no access to fresh water. However, the archipelago is either claimed in part or in entirety by the People's Republic of China, Vietnam, Malaysia, the Philippines, Brunei and the Republic of China (Taiwan). The South China Sea is widely believed to hold major untapped resources of hydrocarbons and important fishing stocks, located close to the disputed islands. The area is also a major lane for international shipping.

Amid the intensity of all these disputes, the U.S. is carrying out amphibious exercises with its Filipino ally, involving almost 7,000 soldiers and sailors from both countries. On Thursday, the two militaries staged highly publicized island landings. The Philippines and the U.S. have both denied that the exercises are targeted at any specific country.

A spokesman for the U.S. Marine Corps said, These exercises take place on a regular basis. This year it happens to be in Palawan. The planning for this took place months ago prior to any events that are currently in the headlines.

U.S. naval vessels are also making simultaneous visits to Vietnam on Wednesday.

In the port of Danang -- a huge U.S. base during the Vietnam War -- three American vessels, including the flagship of the Pacific Fleet, the USS Blue Ridge, are meeting with Vietnamese sailors, their onetime enemies, to conduct a sailor exchange demonstrating non-combatant exercises including maintenance and sea rescue.

The two other U.S. ships in Danang, the USS Chafee and USNS Safeguard, are respectively an advanced guided missile destroyer and a rescue and salvage ship. In a note of friendship and an indication of how much U.S. and Vietnamese relations have changed, the Safeguard flew the Communist Vietnamese flag alongside the Stars and Stripes, something that would have been utterly unthinkable a few short years ago.

But the Chinese navy is also visiting Vietnam. Though much less impressive than the U.S. ships, a Chinese vessel imbued with a deep sense of symbolism pulled into Ho Chi Minh City on Wednesday. Named the Zheng He, after the 15th century explorer admiral who led massive Chinese fleets across the Indian Ocean as far as the coast of East Africa, the Chinese training ship is currently making its way gradually around the world. The effort is diplomatic, but many naval experts see it as an embodiment of China's global naval aspirations.

Few Chinese analysts are convinced that U.S. military engagement with the Philippines and Vietnam is not meant to be a show for China, especially as they consider American intentions to strengthen relations with Asian (and Australian) partners and redirect the nation's geostrategic attention back to the Asia-Pacific. Experts in the U.S. believe that China's neighbors are concerned over its military growth and territorial ambitions, bringing together once unlikely partners. In particular, Vietnam and the U.S., former enemies, are being drawn closer than ever.

Asked on Wednesday about his thoughts on tensions with the Philippines and on the U.S.'s new posture on the Asia-Pacific, Liang Guanglie, China's minister for national defense and a high-ranking general, said the military would respond to China's foreign policy needs. In regards to America's return to the Pacific Liang said, this can't really be called a return to the Asia-Pacific, since they have been here since the past.