Experts at the Center for Strategic and International Studies warn satellite evidence shows the Chinese military is developing a new airstrip in the South China Sea, one that could allow for “more or less constant” surveillance of the internationally disputed waters.

Greg Poling, an expert at the think tank, told Reuters that it is “more likely than not” China is building another airstrip on reef material near the Spratly Islands, the third in the region. It is being built on the seventh known artificial island created by China in the region, all in flagrant violation of international law. The Spratly Islands are considered international territory by all except China, which claims full sovereignty over the entire South China Sea.

The significance of a third airstrip, he argues, is massive. “Clearly, what we have seen is going to be a 3,000-meter airstrip and we have seen some more work on what is clearly going to be some port facilities for ships,” Poling notes. With three airstrips, every variety of Chinese military plane could land and refuel in the region, allowing for “more or less constant” surveillance of the area.

The development on the Spratly Islands, Poling added, will likely impact the tenor of a scheduled meeting between Chinese President Xi Jinping and American President Barack Obama, whose administration has sternly warned China repeatedly that the South China Sea constitutes international waters, and boosted military cooperation with allies like the Philippines and Japan. Japan has a dispute with China over waters in the East China Sea. “It’s going to color the visit. There were already going to be uncomfortable discussions and this isn’t going to make it easier,” Poling warned.

CNN notes that, while other countries like Vietnam, Philippines, Taiwan, and Malaysia also have airstrips in the area, they are nowhere near as large and pose no significant military threat to China or each other.

China already uses its presence in the region to bully nationals from other states. Most recently, the Chinese government declared that Indian government exploration of the international waters in the South China Sea was illegal, with the Chinese Foreign Ministry warning that India “should rethink its oil exploration plans” and Chinese media calling India’s presence in the region “an unwise move.”

Months before, however, the Chinese Foreign Ministry had made a bizarre declaration that its “reclamation” of the South China Sea islands would soon be “complete.” The government did not define the term “reclamation,” leaving open-ended the possibility for more construction on land it had already “reclaimed.”

“It is learned from relevant Chinese competent departments that, as planned, the land reclamation project of China’s construction on some stationed islands and reefs of the Nansha [Spratly] Islands will be completed in the upcoming days,” the statement claimed in June. “After the land reclamation, we will start the building of facilities to meet relevant functional requirements.”

A week later, the Chinese government issued a statement insisting its work in the region was intended to improve weather reports, and not threaten any nation militarily.

This language proved unpersuasive for many neighboring countries, the Philippines protesting the loudest. Philippines Defense Department spokesman Peter Paul Galvez accused China of using “deceitful rhetoric claiming peaceful efforts” in a demand for China to stop its military development in the region. “We call on China’s government to show its sincerity by, at the least, stopping all ongoing construction and militarization activities and to refrain from restricting freedom of flight and navigation,” he demanded.

The Philippines has also condemned China for creating an environmental disaster in the region, as its construction has destroyed at least 17 distinct reefs in the South China Sea, all individual ecosystems on which China has built artificial islands.

In response to these allegations of misconduct, Chinese Vice Admiral Yuan Yubai said at a military conference this weekend that China is within its full rights to engage in construction in the South China Sea because “China” is right there in the name. “The South China Sea, as the name indicates, is a sea area that belongs to China,” he said, “and the sea from the Han Dynasty a long time ago where the Chinese people have been working and producing from the sea.”