Defense Ministry spokesman Yang Yujun dismissed media reports saying that China is building a second aircraft carrier in Shanghai which will be launched late this year in Thursday's regular press briefing.

"Such reports are inaccurate. We will take into consideration national economic development, the needs of national defense and military construction when we make further plans for our carriers," Yang said at the news briefing, two days after China's first aircraft carrier Liaoning was commissioned to the People's Liberation Army (PLA) Navy.

He also said that China's carrier-based aircraft were developed from China's own aircraft with independent intellectual property rights.

According to Lan Yun, senior editor of the military magazine Modern Ships, the press briefing was lacking in information.

"Yang's answer to the second carrier was also ambiguous. He did not say which part of the report was inaccurate, so people can assume that China is building follow-up carriers, but only the second one will not be launched late this year, or it will not be built in Shanghai," he said. "Besides, the long-awaited announcement did not even mention the type of the carrier-based fighter."

Since the commissioning of the carrier Liaoning, speculation surrounding China's carrier-based aircraft has been on the rise, both in domestic defense forums and foreign media reports.

The New York Times on Tuesday quoted unnamed military experts as saying that China "does not have planes capable of landing on the carrier".

The newspaper quoted a Singaporean researcher as saying that Chinese pilots have no choice but practice simulated carrier landings on land in Chinese J-8 aircraft.

"This report is highly irresponsible and not in line with the facts," Bai Wei, former deputy chief editor of the Aviation World Monthly magazine, told the Global Times.

"China has developed its own double-seat trainer specializing in aircraft take-off and landing and its own carrier-based fighter dubbed by the outside as J-15," he said.

Photos of these aircraft have been circulating on the Internet, and have also been published in the mainland's official military and aviation magazines.

"They are not secrets," Bai said.

The images of the landing wheel traces on the carrier flight deck and footage from CCTV also suggested that fixed-wing aircraft have at least carried out carrier touch-and-go landing, which is a necessary step toward actual carrier landings, he noted.

When asked to confirm reports that the Chinese navy will create an aircraft carrier formation in the future and build an aircraft carrier base in Qingdao, Shandong Province, Yang said, "The formation is generally made up of the aircraft carrier itself, escort vessels, submarines and aircraft. China will study the issue in accordance with the development and real needs of the aircraft carrier."

Despite the fact that the Liaoning still has a long way to go toward operational capability and is yet to form its own combat group, some foreign observers believe that the commissioning of the Liaoning is a milestone that has marked yet another step toward building up a blue water navy.

"While (the Chinese navy's) acceptance of this 'starter carrier' is the first step in a long journey, it is a journey that will take place in full view of the world, and one that will ultimately take Beijing to a new place as a great sea power," Andrew S. Erickson, a China naval specialist at the US Naval War College, wrote on his blog.

Also on Thursday, in response to Japanese media reports that two PLA Navy frigates made patrols in waters around the Diaoyu Islands last week, Yang confirmed that Chinese naval ships have carried out patrols and military training in the area, saying that it was totally legal and legitimate for Chinese vessels to conduct combat patrol and training in waters administered by China.

The row between China and Japan is unrelated to the timing of the carrier commission ceremony, which was set according to the development of the carrier project, said Yang.

Yang also said the country's use of drones, or unmanned aerial vehicles, over Huangyan Island, the Nansha Islands and their adjacent waters is "justified and legal," and warned that China opposes any military provocation in the South China Sea.

Yang made the remarks in response to comments by a Philippine Department of National Defense spokesman that Chinese drones may be shot down if they enter the above-mentioned airspace.

China has indisputable sovereignty over Huangyan Island, the Nansha Islands and their adjacent waters, Yang responded.

"Therefore, Chinese aircraft flying in the airspace in question is justified and legal," he said.

China's State Oceanic Administration said on Sunday that China will promote the use of drones to strengthen the nation's marine surveillance, and step up efforts to enhance its surveillance of the islands and islets including the Diaoyu and Huangyan.

Yang also rejected media reports that Chinese-made refractories used in manufacturing the boilers of the Indian Navy carrier Vikramaditya were damaged during the ship's sea trials.

"According to our investigation, Chinese companies producing these materials have never exported such products to Russia," Yang said.

The Vikramaditya has failed sea trials due to boiler failure and its delivery to the Indian Navy may again be delayed by almost a year, according to Russian media reports this week.

Xinhua contributed to this story