Story highlights Jane's Defence Weekly: China building island in the South China Sea that could accommodate airstrip.

Waters are bitterly contested by Vietnam, Philippines and other countries in the region.

Report says land mass is more than 3,000 meters long and a harbor is also being built.

China says that construction is legitimate, will improve soldiers' living standards.

China is building an island in the South China Sea that could accommodate the country's first airstrip in bitterly contested waters, according to satellite images analyzed by IHS Jane's Defence Weekly.

Reclamation at Fiery Cross Reef on the western edge of the disputed Spratly islands is creating a land mass that is more than 3,000 meters (2 miles) long and between 200 to 300 meters (650 to 980 feet) wide -- large enough to construct a runway and apron, the publication said.

The South China Sea is the subject of numerous rival -- often messy -- territorial claims, with China, Brunei, Malaysia, the Philippines, Taiwan and Vietnam disputing sovereignty of several island chains and nearby waters.

The areas in dispute include fertile fishing grounds and potentially rich reserves of undersea natural resources.

Photos: China reclaiming land in disputed waters Photos: China reclaiming land in disputed waters China reclaiming land in disputed waters – Airbus Defence and Space imagery dated November 14, 2014 shows land reclamation operations under way at Fiery Cross Reef. Multiple operating dredgers provide the ability to generate terrain rapidly. Operating from a harbour area, dredgers deliver sediment via a network of piping. Image courtesy IHS Jane's Defense Weekly. Hide Caption 1 of 2 Photos: China reclaiming land in disputed waters China reclaiming land in disputed waters – Airbus Defence and Space Imagery dated August 8, 2014 shows the beginning of land reclamations at Fiery Cross Reef in the South China Sea. Image courtesy Jane's Defense Weekly. Hide Caption 2 of 2

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Jane's said that Malaysia, the Philippines and Taiwan had built airfields on reefs and islands in the contested waters.

"The work at Fiery Cross thus brings parity but is likely to cause alarm among the other claimants," the report said.

"Given its massive military advantage over the other claimants in terms of quantity and quality of materiel, this facility appears purpose-built to coerce other claimants into relinquishing their claims and possessions, or at least provide China with a much stronger negotiating position if talks over the dispute were ever held."

The report said that dredgers were creating a harbor large enough to receive tankers and warships.

Construction 'legitimate'

But Maj. General Luo Yuan of China's People's Liberation Army (PLA) told the state-run Global Times that construction was justifiable and that the infrastructure would improve the living standards of soldiers stationed there.

"The construction and maintenance of facilities and other activities we conducted on these islands are within our sovereign rights and they are legitimate," he added.

At a briefing on Monday, Hua Chunying, China's Foreign Ministry spokesperson, said that China has "indisputable sovereignty" over the islands in the South China Sea and said the construction would help in case of search and rescue efforts.

China's stance on maritime disputes has put it at odds with many of its smaller neighbors.

Earlier this year, it moved an oil rig near the disputed Paracel Islands triggering anti-Chinese riots in Vietnam

Relations have also soured with the Philippines.

On Monday, a Philippines court convicted nine Chinese fishermen of poaching hundreds of endangered giant sea turtles from a disputed shoal in the South China Sea. They were each fined nearly $103,000 but face no jail term.

Diplomatic initiatives

The United States has supported efforts by regional group ASEAN to draw up a code of conduct to defuse maritime disputes, but China has said it prefers to deal with the issue bilaterally.

On Friday, a Pentagon spokesman told Agence France-Presse (AFP) that the U.S. wanted China to stop its land reclamation program and engage in diplomatic initiatives.

In a speech at the G20 summit earlier this month, President Barack Obama said the U.S. planned to deepen its diplomatic and military engagement in Asia and would work to ensure that big nations don't "bully the small."