Tensions in the disputed South China Sea has been mounting amid reports and satellite images of China's construction of military installations and artificial islands
Here's a closer look at the key military installations and developments in the disputed Paracel and Spratly islands:
Woody Island, also known as Yongxing Island
- The site of the largest Chinese presence on the Paracels, Fox News first reported on Feb 16 that China had deployed surface-to-air missiles here over the course of the previous week.
- Military experts say the HQ-9 missile batteries, guided by radar tracking systems, have a range of 200km.
- In 2012, China established Sansha City and a city government here to administer the Paracels and Spratlys. More than 1,000 civilians reportedly live in the city, with Xinhua news agency reporting in January that regular flight service will be launched to the city.
- On Feb 13, news website The Diplomat reported that Chinese helicopter landing sites were being built here, and could be used to support anti-submarine warfare helicopters.
- On Jan 30, US Navy guided-missile destroyer Curtis Wilbur sailed within 12 nautical miles of Triton Island, prompting angry rebukes from China.
- On Nov 8 last year, the US flew two Air Force B-52 bombers around the Spratlys in what it said was a routine mission. A month later, a US B-52 bomber flew near Cuarteron Reef but the US Defence Department said that it had mistakenly entered disputed territory on a training mission.
- On Feb 22, Washington think-tank Centre for Strategic and International Studies (CSIS) reported that China's construction of facilities, which could be a high-frequency radar installation, are nearly complete.
- The island already has a buried bunker, helipad, communications equipment and a quay.
- Experts at CSIS consider developments here particularly important as it would boost China's ability to monitor surface and air traffic across the southern portion of the South China Sea, allowing it to monitor surface and air traffic coming north from the Strait of Malacca. China already has radar coverage of the northern portion of the South China Sea from the Paracel Islands.
- On Dec 10 last year, a US B-52 bomber flew within two nautical miles of the reef. US officials said bad weather had caused the pilot to fly off course and that it was an unintentional move during a routine mission.
Fiery Cross Reef
- On Jan 2 and Jan 6 this year, China announced the first successful test landings of civilian airliners on the 3,000m air strip.
- The airstrip, which was completed last September, can be used for both civilian and military airplanes.
- It also houses helipads, air defence guns and possibly has a radar tower under construction.
- On Oct 27 last year, a US guided-missile destroyer USS Lassen passed within 10km of the reef in a 115km-long freedom of navigation patrol. A Chinese guided-missile destroyer and naval patrol ship shadowed it and gave warnings, according to China's Defence Ministry.
- Until 2014, when China reclaimed land here, Subi was submerged at high tide. An airstrip is currently under construction here.
- It was reported last September that China was carrying out preparatory work to build an airstrip here.
- This reef is hotly disputed because while it lies within the exclusive economic zone of the Philippines, it is also relatively close to land features claimed by other claimants.
- It hosts military facilities, shelter for fishermen and cement plants.
Itu Aba, also known as Tai Ping Island
- On Jan 28 this year, Taiwanese President Ma Ying-jeou ignored US criticism and flew there to reaffirm Taipei's sovereignty. The island has an airstrip, hospital and fresh water supply.
- 180 people live here, most of them coast-guard personnel.
- Taiwan has just finished a US$100 million (S$143 million) port upgrade and built a new lighthouse.
SOURCES: AFP, REUTERS, CENTRE FOR STRATEGIC AND INTERNATIONAL STUDIES, THE DIPLOMAT