
New pictures have emerged appearing to show how China is rapidly building a new island - on a barrier reef.

Aerial photographs show dozens of cranes, boats and dredgers at Mischief Reef in the South China Sea - 250 km from the Philippine island of Palawan.

China is reclaiming about seven reefs in the Spratly archipelago, according to Philippine officials, amid claims there will eventually be an island in the area big enough to host a 3,000 metre airstrip.

Under construction: Pictures have emerged appearing to show how China has built a new island on a barrier reef in the South China Sea - in just ten weeks

China's creation of artificial islands is happening so fast that Beijing will be able to extend the range of its navy, air force and coastguard before long, experts say.

According to a report in The Diplomat, Mischief Reef has been filled in with sand and coral over an area covering 2.42 square kilometres in just months.

It says satellite images at least 23 dredgers as well as 24 large 'construction related vessels' in the lagoon along with dozens of large concrete mixing trucks.

The website also claims that only two small sites of dredging and land fill activity were 'detectable' at Subi Reef - 14 miles from the Philippine outpost Thitu Island - as of February 6, 2015. But by April 17, it says, satellite images show how an island had been built on top of the reef.

Major Ferdinand Atos,the highest-ranking soldier on Thitu, told reporters: 'In the last two years we have seen rapid development. They are getting closer to us. It's a threat.

But Ian Storey, a South China Sea expert at Singapore's Institute of South East Asian Studies, said the Philippines might struggle to sustain its holdings on Thitu and elsewhere in the Spratlys.

'Once (China) has all its facilities up and running, it will put the Philippines in a much more difficult position,' Storey said. 'The Chinese will be able to harass Philippine coastguard and naval vessels on a more regular basis ... they could try to impose blockades on other Philippine-occupied atolls, including Pagasa.'

Building work: China is reclaiming about seven reefs in the Spratly archipelago, according to Philippine officials, amid claims there will eventually be an island big enough to host a 3,000 metre airstrip

China recently warned Philippine air force and navy planes at least six times to leave areas around the Spratlys, the Philippine commander responsible for the region said last week.

Beijing claims sovereignty over most of the South China Sea, through which $5 trillion in ship-borne trade passes every year. The Philippines, Vietnam, Malaysia, Taiwan and Brunei also have overlapping claims.

Last month, China offered a detailed defence of its reclamation work, saying the new islands would provide civilian services such as weather forecasting and search and rescue facilities that would benefit other countries.

It has also accused other claimants, including the Philippines, of undertaking major reclamation work.

Dredging at Subi Reef showed a series of landmasses being created that, if joined together, would provide enough land for a 3,000-metre (3,281-yard) airstrip, IHS Janes Defence Weeklysaid last month.

China's Foreign Ministry did not immediately respond to a request for comment on the observations by reporters when they travelled to Thitu - a trip organised by the Philippine military.

The coral-fringed Thitu, some 280 nautical miles from the Philippines, is the biggest island occupied by Manila in the contested region.

Philippine soldier Tychico Octobre patrols a beach in Pagasa Island (Thitu Island) at the Spratly group of islands in the South China Sea, west of Palawan

Philippines military chief General Gregorio Catapang Junior points to a reference map of islands in the Spratly group of islands during his visit to Thitu Island in the South China Sea

The 37-hectare (91-acre) island boasts fresh water, a small number of Philippine troops and a civilian population of about 100 people who take advantage of government subsidies to live here.

There is little sign of any upgrading.

The runway is no more than an unpaved track dotted with tufts of grass. Blue ocean water washes over one end while erosion is eating away at other sections.

The only sign that the island hosts a military base are two 40 mm anti-aircraft guns on opposite sides of the runway.

Thitu needs a proper wharf to spur tourism and fisheries, said Eugenio Bito-onon, mayor of Kalayaan, a municipality in the island province of Palawan that administers the island.

The military had developed a plan to upgrade the nine islands and reefs it holds in the Spratlys.