China has nearly completed a military-length runway on one of the artificial islands it has built in the disputed South China Sea, according to satellite photos published by a maritime monitoring group.
The Asia Maritime Transparency Initiative (AMTI) says China continues to pave and mark the 3,000-meter airstrip, which analysts say is capable of accommodating any plane in China's air force fleet.
Additional military facilities - including two helipads, up to 10 satellite communications antennas, and a possible radar tower - are also being built on the Fiery Cross Reef, said the group's online report.
The island is about 2,7 square kilometers in size and has a partially developed port with nine temporary loading piers, according to the AMTI, which is affiliated with the Center for Strategic and International Studies.
The reef is one of seven locations in the Spratly Islands where China is reclaiming land, and in some cases building military facilities, in apparent attempt to expand its military presence and enforce its claims.
The Philippines, Vietnam, Malaysia, Brunei and Taiwan also claim parts of the South China Sea, which is rich in natural resources, is a main trade route, and holds important symbolic and national value.
China has recently said it is finished with some of the island-building efforts in the Spratlys, but it has not specified which projects this applies to or when the rest of the land reclamation will be finished.
On Tuesday, Chinese foreign ministry spokeswoman Hua Chunying said facilities will continue to be built on the islands, which she acknowledged have both military and civilian purposes.
One of the islands where land reclamation appears to be mostly finished is the Johnson South Reef. The AMTI report said the island features two helipads, up to three satellite communications antennas, and a large multi-level military facility.
The United States has demanded an immediate end to the South China Sea island-building, saying it is out of step with international norms and is raising the risk of eventual clashes in the region.
The U.S., which has an extensive military presence in East Asia, has flown planes near the islands, angering China. The Pentagon has said it may increase the flights and send ships to the area to enforce freedom of navigation.
China says it has indisputable sovereignty to almost the entire 3.5-million-square-kilometer South China Sea and says it is not disrupting freedom of navigation. It has called on Washington to stay out of the matter.