China outlined a defence strategy on Tuesday to boost its naval capability farther from its shores, saying it faced a grave and complex array of security threats including in the disputed South China Sea.
In a policy document issued by the State Council, the country's cabinet, it vowed to continue growing its "open seas protection" and criticized neighbors who take "provocative actions" on its reefs and islands.
The document comes as tensions rise over China's increasingly assertive posture in the disputed waters of the South China Sea, where Beijing has engaged in land reclamation in the Spratly archipelago.
China, which claims most of the South China Sea, criticism Washington after a US spy plane flew over areas near the reefs last week, with both sides accusing each other of stoking instability in the region.
It has overlapping claims with the Philippines, Vietnam, Malaysia, Taiwan and Brunei in the South China Sea, through which $5 trillion in ship-borne trade passes every year.
Yang Yujun, a spokesman for the Ministry of Defense, said in a briefing on Tuesday China's reclamation activities in the Spratly archipelago were comparable with construction of homes and roads on its mainland.
"From the perspective of sovereignty, there is absolutely no difference," he said.
He said some countries with "ulterior motives" had unfairly characterized China's military presence and sensationalized the issue. Surveillance activities in the region were increasingly common, and China would continue to take "necessary measures" to respond, Yang said.
"Some external countries are also busy meddling in South China Sea affairs; a tiny few maintain constant close-in air and sea surveillance and reconnaissance against China," the strategy paper said in a thinly veiled reference to the United States.
It also said China's air force would shift its focus from territorial air defense to both offence and defense, and building airspace defenses with stronger military capabilities.
The People's Liberation Army's nuclear force, known as the Second Artillery Corps, would also strengthen its capabilities for deterrence and nuclear counterattack as well as medium- and long-range precision strikes, the paper said.
It also said the military would strengthen security in areas critical to China's overseas interests, without giving details.