China says it can use force to kick out nations illegally to seize more islands in the South China Sea, but Beijing is now showing restraint, a top Chinese diplomat has said.

“The Chinese government has the right and the ability to recover the islands and reefs illegally occupied by neighboring countries,” Vice Foreign Minister Liu Zhenmin said Tuesday in Beijing, speaking about the South China Sea disputes but not naming any particular country.

The Spratly Islands is an archipelago where China, Vietnam, the Philippines, Malaysia, Taiwan and Brunei have sovereignty claims, which have been escalating tensions in the region.

“But we haven’t done this [seized the islands]. We have maintained great restraint with the aim to preserve peace and stability in the South China Sea,” Liu added.

All six but one – Brunei – claimants of the conflict have military fortifications on the Spratly islands, which raises concerns over a high risk of military confrontation in the region, in case the tensions get particularly hot.

China has been the most active player of the dispute, beefing up its claim to the islands by reclaiming a number of reefs in the archipelago and building infrastructure there. Other sides of the dispute have repeatedly called for the U.S. to do something about China’s threatening actions.

“We have a country that is building 3 kilometer-long airstrips and port facilities, supposedly for its coast guard,” Malaysian Deputy Prime Minister Ahmad Zahid Hamidi said, speaking at the opening of a party congress in a Malaysian city on Saturday.

“Does this make sense when that country’s mainland is more than 3,000 kilometers away?”

China turns disputed South China Sea into military outposts

Those who monitor China’s actions in the South China Sea say Beijing is turning the artificial islands into military outposts. They claim that the long runways, which China has been focused on building in the disputed area, are required to host heavier warplanes. However, China insists that its primary goal in the South China Sea is civilian development.

“Actually, the larger they are, the more civilian benefits they will bring,” Liu said, speaking about the long runways, adding that rescue efforts after the disappearance of Malaysian Airlines flight MH370 in 2014 indicated a lack of capabilities in the South China Sea.

If China gets to control the Spratly Islands, it gets the key to controlling waters through which $5 trillion in trade passes every year, mostly to and from China. The disputed area is also extremely rich in natural resources, which each side of the dispute wants to claim as their own. The South China Sea is also believed to have vast reserves of hydrocarbons under its seabed.

The U.S., meanwhile, is trying to bring down the Chinese threat in the region by sending its warships, warplanes and drones to the disputed area that China claims its own sovereignty.

But the Chinese are not happy about it, calling U.S. actions “provocative.”

U.S. risks unleashing nuclear war with China

Moreover, Beijing said it is ready to respond to further U.S. provocations in South China Sea, while China’s defense minister urged Washington to stop threatening Beijing’s sovereignty and the country’s national and security interests after an incident of a U.S. warship sailing in the South China Sea in early November.

The warning was issued by Chinese Defense Minister Chang Wanquan to U.S. Defense Secretary Ash Carter last week in Kuala Lumpur, where the ministers met at the Association of South East Asian Nations (ASEAN) defense chiefs meeting.

China’s defense minister also warned Washington against sending further patrols to the islands in the South China Sea, which Beijing claims its own exclusive sovereignty.

In early November, the USS Lassen sailed inside the 12-mile nautical zone around Subi Reef in the Spratly Islands archipelago. This reef is one of seven reefs that Beijing has artificially built in order to claim its sovereignty over the Spratly Islands and the sea around it, including waterways that carry $5 trillion in trade annually.

Immediately after the incident with the U.S. warship, China’s Foreign Ministry issued a statement, saying that such actions are damaging “peace and stability in the region.” Beijing also claims that American “provocations” in the disputed area threaten the safety of people living on the islands.

China vs. U.S.: World War 3 over some tiny islands?

China’s top officials and diplomats have expressed their outrage over the incident with the U.S. warship sailing in the South China Sea, accusing the U.S. of “provocations” and of escalating tensions in the region.

Washington then replied to Beijing’s criticism, saying that it will sail and fly wherever it wants in international waters and airspace. The U.S. Navy said that additional patrols could take place in the coming weeks, which raises concerns whether China will be as “restrained” as it was during the incident or whether it will be prepared to respond militarily.

Several days after the incident, Beijing responded to U.S. “provocations” by conducting training of its naval jets around the disputed artificial islands in the South China Sea.

Critics argue that there are two scenarios of the South China Sea dispute. In the best-case scenario, the dispute will be eventually settled diplomatically between all sides of the conflict. In the worst-case scenario, the U.S. will be sending more of its warships, warplanes and drones into the disputed area, and the Chinese will be likely to respond with force.

One thing will lead to another, and we will face the World War 3 over some tiny islands in South China Sea.