Beijing defended its construction of what it called defensive facilities in the disputed South China Sea on Tuesday, saying the moves were not directed at any specific country, according to a Defense Ministry spokesman.

“China’s garrison on the islands and reefs in the Nansha Islands and the deployment of necessary national defense facilities are the natural rights of sovereign states,” spokesman Ren Guoqiang said in a statement posted to the ministry’s website.

China refers to the South China Sea’s Spratly chain as the Nansha Islands. The Spratlys are home to seven Chinese-held man-made islands that it has fortified with deep-water piers, military-grade airfields, defensive weapons and barracks.

Ren said the facilities help protect navigation safety, “serve to ensure regional peace and stability and are not directed at any country.”

He was answering a question about whether China’s military deployments were a response to missions by the U.S. Navy to challenge Beijing’s claim to virtually the entire South China Sea. The Philippines, Vietnam, Malaysia, Taiwan and Brunei all have overlapping claims in the strategic waterway.

Tuesday’s remarks came on the heels of a report in the Wall Street Journal on Monday citing a Pentagon official who said that China “has deployed military jamming equipment to its Spratly Island outposts.”

That report said that the new jamming equipment was deployed within the past 90 days on Fiery Cross Reef and Mischief Reef, according to U.S. intelligence assessments.

China is currently in the midst of a military modernization program heavily promoted by President Xi Jinping, who has overseen a shift in focus toward creating a more potent fighting force, including projects such as building a second aircraft carrier, integrating stealth fighters into its air force and fielding an array of advanced missiles that can strike air and sea targets from long distances.

The Chinese military has also seen its forces drill to punch further into the Western Pacific with what it calls “regular” exercises.

Late last month, the Chinese Air Force conducted a series of exercises in the South China Sea and Western Pacific, where it sent advanced fighter jets and heavy bombers through Okinawa’s Miyako Strait, labeling the exercises “rehearsals for future wars.”