Great Wall Of Sand - China has been building a "Great Wall of sand" with the use of an unparalleled program of land reclamation in the South China Sea. Because of this great wall of sand, many are having "serious questions" about the country's intentions for it, according to the BBC.

Apart from the questions, concerns were also raised about the possibility of military confrontation in the disputed waters, said U.S. Pacific Fleet Commander, Admiral Harry Harris, Tuesday.

Harris announced the great wall of sand during a speech in Australia, and he accused China of building the wall over areas that have already been claimed by several nations, which include Vietnam, Philippines and Taiwan, according to Fox News.

"China is building artificial land by pumping sand on to live coral reefs - some of them submerged - and paving over them with concrete. China has now created over 4 square kilometers (1.5 square miles) of artificial landmass," said Harris of the great wall of sand.

"When one looks at China's pattern of provocative actions towards smaller claimant states - the lack of clarity on its sweeping nine-dash line claim that is inconsistent with international law and the deep asymmetry between China's capabilities and those of its smaller neighbors - well it's no surprise that the scope and pace of building man-made islands raise serious questions about Chinese intentions," Harris continued during his speech on the great wall of sand.

Satellite images reportedly show rapid construction of the great wall of sand, which were placed on various coral reefs and rocks controlled by China within the disputed Spratly Islands. These include harbors, piers, helipads, buildings and one potential airstrip, according to experts.

Last month, Jen Psaki, State Department spokeswoman, also expressed her concerns over the program on the great wall of sand being an attempt to "militarize outposts on disputed land features."

According to Harris, despite the great wall of sand, the U.S. is continuing to advocate to all claimants to adhere to the 2002 China-ASEAN Declaration of Conduct, which says that all parties should be committed to "exercise self-restraint in the conduct of activities that would complicate or escalate disputes and affect peace and stability."

"How China proceeds will be a key indicator of whether the region is heading toward confrontation or cooperation," he said.

According to the U.S., it has national interest towards the peaceful resolution of the disputes over the islands because the region is crucial for world trade.

Harris also said that the United States is on track to reposition 60 percent of its navy to the Pacific Fleet by 2020.

"By maintaining a capable and credible forward presence in the region, we're able to improve our ability to maintain stability and security," said Harris. "If any crisis does break out, we're better positioned to quickly respond."

Meanwhile, according to China, its territorial claims have historical basis and is objecting to U.S. meddling over the great wall of sand and other activities they have been performing in the region.

Last month, Chinese Foreign Minister Wang Yi said China was merely carrying out "necessary construction on its own islands and reefs." He added that the country will upholding freedom of navigation in the busy shipping waters of the South China Sea and resolving disputes through "direct dialogue" and consultation, reported the Washington Post.

"The construction does not target or affect anyone," Wang Yi said at a news conference. "We do not accept criticism from others when we are merely building facilities in our own yard. We have every right to do things that are lawful and justified."

Apart from building the great wall of sand which is causing great concern over territorial issues in the region, last year, anti-Chinese violence broke out in Vietnam after China reportedly moved a drilling rig into disputed waters of the Paracel Islands. Responding to a BBC report on the land reclamation, Hua Chunying, China's foreign ministry spokesman, said that the country's operations in the Spratly Islands fell "entirely within China's sovereignty and are totally justifiable".