Satellite view of one of the islands part of the Paracel Islands in the disputed South China Sea.
Lu clarified that the relevant Chinese law has explicit provisions on foreign military vessels' entry into the territorial sea of China.
"(Beijing) said some red lines, we said some red lines.
China's claims in the South China Sea, through which about $5 trillion (3.75 trillion pounds) in shipborne trade passes each year, are contested by Brunei, Malaysia, the Philippines, Taiwan and Vietnam. He said, "Whatever happens, happens".
China China's landing of H-6K bomber aircraft at Woody Island earlier this month has raised tensions, and in response the USA has uninvited China from the 2018 Rim of the Pacific (RIMPAC) Exercise.
The secretary took the opportunity to allay fears and addressing criticism by stressing that the Philippines has not lost a single inch of territory to China during the Duterte administration, and if it is proven otherwise, he will demit office. Cayetano said his department was repeatedly told to "file a protest" over Beijing's actions in the South China Sea, CNN reported. "We are taking all diplomatic actions at the right time", he said.
The government of Filipino President Rodrigo Duterte has fired off a stern warning to China regarding the natural resources in the South China Sea region. He said the Philippines could seek the help of its ally countries to pressure China to stop its military activities.
It also aids military development, says military analyst Song Zhongping.
China on Sunday voiced strong dissatisfaction and firm opposition to two USA warships trespassing into China's territorial waters off the Xisha Islands.
"We conduct routine and regular Freedom of Navigation Operations (FONOPs), as we have done in the past and will continue to do in the future", U.S. Pacific Fleet said in a statement.
The foreign ministry issued a statement expressing "resolute opposition" to the USA sail-by of the territory in the disputed Paracel Island chain on Sunday.
The chief spokesman for China's Ministry of National Defense, Senior Col. Wu Qian, said that the United States "gravely violated Chinese sovereignty".
Australia's News.com notes that global law does not, in fact, support China's claim of ownership over 80 percent of the South China Sea.
To register its objection to Beijing's growing militarization of its artificial islands, the United States military on May 23 disinvited China from biannual RIMPAC naval exercises. While this activity had been arranged a very long time ahead of time, and comparable tasks have turned out to be standard, it comes at an especially delicate time and days after the Pentagon uninvited China from a noteworthy USA facilitated maritime exercise.