BEIJING (Reuters) - China accused the Philippines on Tuesday of deliberately trying to scare people by saying China had warned a small civilian plane carrying Philippine officials it was trespassing as they inspected an island in the disputed South China Sea.

Chinese dredging vessels are purportedly seen in the waters around Fiery Cross Reef in the disputed Spratly Islands in the South China Sea in this still image from video taken by a P-8A Poseidon surveillance aircraft provided by the United States Navy May 21, 2015. REUTERS/U.S. Navy/Handout via Reuters ATTENTION EDITORS - THIS PICTURE WAS PROVIDED BY A THIRD PARTY. REUTERS IS UNABLE TO INDEPENDENTLY VERIFY THE AUTHENTICITY, CONTENT, LOCATION OR DATE OF THIS IMAGE. THIS PICTURE WAS PROCESSED BY REUTERS TO ENHANCE QUALITY. EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS - RTX1DZNB

The Philippines said the incident happened on Jan. 7 to an aircraft inspecting Thitu Island in the Spratlys, where Manila plans to set up surveillance equipment this year, as their aircraft flew near a Chinese man-made island.

Chinese Foreign Ministry spokesman Hong Lei repeated that China has sovereignty over the Spratlys and that the Philippines had illegally occupied eight islands there since the 1970s, including Thitu, and had been building on them.

“The Philippines’ comments are just frightening words to scare people, deliberately exaggerating regional tensions with treacherous intent, and its plots will not succeed,” Hong said, when asked about the warning to the Philippine aircraft.

The Philippines plans to install a $1 million satellite-based system on Thitu to track commercial flights over the South China Sea, after China landed its first test flights this month on a reef it built in the Spratly islands.

Hong said that any activities by the Philippines on the islands it occupies were illegal.

China’s increasing military presence in the Spratlys has stirred fears it could lead to an air defense zone, which would escalate tension with other claimants, and the United States, in one of the world’s most volatile areas.

China claims almost the entire South China Sea, believed to have huge oil and gas deposits, but Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have claims in the sea, through which about $5 trillion in trade passes every year.

The Philippines and Vietnam protested against China’s test flights on the Fiery Cross Reef this month.

“The concerns about the recent activities of China along with the reclamation activities and construction of airstrips in the disputed territory is shared by other countries as it adds to the tension in the region,” said Herminio Coloma, Philippine presidential communications secretary.

It “causes concern about the freedom of freedom of navigation and overflight in the area”, Coloma added.