The dispute over the strategic waterways of the South China Sea has intensified, pitting a rising China against its smaller and militarily weaker neighbors who all lay claim to a string of isles, coral reefs and lagoons known as the Spratly and the Paracel islands. Only about 45 of them are occupied. The area is the third-busiest global shipping lane, rich in fish and potentially gas and oil reserves, but has emerged as a possible flashpoint involving world powers and regional claimants.
A look at some of the most recent key developments:
CHINA'S ISLAND CONSTRUCTION CAPTURED ON SATELLITE
A series of high-resolution satellite images, the latest of which were taken in February and March and released by defense publication IHS Jane's, show that China has intensified the construction of artificial islands by dredging sand from submerged coral reefs and building up land mass, sometimes doubling or tripling the size of existing features. Among at least half a dozen islands being reconstructed, work on Fiery Cross Reef has attracted most attention because of its speed and scale. According to Jane's, the new island is already big enough for a 3,000-meter (9,500-foot) runway able to accommodate big military planes.
Landfill work on Subi Reef also reportedly includes a runway, and dredging activities on Mischief Reef could accommodate another runway, according to analysts.
The commander of U.S. forces in the Pacific, Adm. Samuel Locklear, says the construction provides ability for China to deploy, base and resupply ships and exert greater influence over the contested area.
China could also deploy long-range radars and advanced missile systems as a means of enforcing a future air defense zone over the area. Such a zone would require foreign aircraft to file flight plans, identify themselves and follow the instructions of Chinese flight controllers.
China's Foreign Ministry spokesman Hong Lei says the work is largely to improve living conditions for people in the area and help with weather forecasting and search and rescue work.
Although China says its sovereignty claim poses no barrier to freedom of navigation in the South China Sea, its actions often speak differently, particularly when they involve the movements of foreign militaries.
ASEAN ISSUES STRONGER STATEMENT, CHINA TAKES NOTICE
The leaders of the 10-member Association of Southeast Asian Nations — which includes the Philippines and Vietnam, the most vocal critics of China — issued a statement condemned Beijing. After an annual summit hosted by Malaysia, ASEAN said that China's landfill work "eroded trust and confidence and may undermine peace, security and stability in the South China Sea." It said members instructed their foreign ministers to "urgently address this matter constructively."
However, Malaysia said separately that ASEAN would avoid confrontation, after the Philippines urged the group to "stand up" to China and halt the reclamation work.
China responded by saying it was "severely concerned" over the statement. Spokesman Hong Lei said that reclamation and construction work was entirely legal and shouldn't be questioned.
PHILIPPINES SAYS CHINA HARASSES AIR PATROLS
The Philippines says China has challenged its air reconnaissance six times since last month and "appears to be in effect imposing" an air defense zone over the disputed area, according to Vice Adm. Alexander Lopez.
A Philippine air force plane heard a radio recording while approaching Subi Reef on April 19: "Foreign airplane, you are approaching my military security area, please go away quickly in order to avoid misjudgment." Lopez said such warnings are dismissed and pilots reply that they are navigating international space.
Chinese Foreign Ministry spokesman Hong Lei said that Philippine planes had "illegally flown over Chinese waters on numerous occasions recently" and that Chinese forces had issued a radio warning.
PHILIPPINES, US HOLD LARGEST DRILLS NEAR ISLANDS
More than 11,500 American and Filipino troops held their largest exercises near the South China Sea, simulating an amphibious attack to retake an island.
The drills took place in Zambales province, which includes Scarborough Shoal, which was seized by China in 2012.
"If China were to successfully claim the entire South China Sea, which is what they do claim, and apply their interpretation of the rights of the country, then it would severely restrict the military operations of the United States, Japan, other countries. So it's really unacceptable to the United States." — Retired Adm. Dennis Blair, commander U.S. forces in the Pacific 1999-2002.
Associated Press writers Hrvoje Hranjski in Bangkok, Christopher Bodeen in Beijing and Teresa Cerojano in Manila, Philippines, contributed to this report.