BEIJING (REUTERS)- New satellite images show China may be building its first indigenous aircraft carrier in the northeastern port of Dalian, according to IHS Jane's Defense Weekly, which has released the pictures.

Little is known about China's aircraft carrier programme, which is a state secret, though Chinese state media have hinted new vessels are being built. The Pentagon, in a report earlier this year, said Beijing could build multiple aircraft carriers over the next 15 years.

Taiwan's Defence Ministry, in a report obtained by Reuters last month, said China was building two aircraft carriers that will be the same size as its sole carrier, a 60,000-tonne refurbished Soviet-era ship.

IHS Jane's said the unidentified hull was in an advanced state of construction at a shipyard in Dalian. "While a conclusive identification of the hull as an aircraft carrier cannot be made until work is observed on the upper decks and potential flight deck, the slow pace of assembly and outline suggests a military hull under construction," it said in an emailed sent on Thursday (Oct 1).

The dry dock is "associated" with the refit and repair of China's existing carrier, the Liaoning, IHS Jane's said.

The ship could also be a new class of amphibious assault ship or helicopter carrier, it added.

The Taiwanese report obtained by Reuters said one of the new vessels is being built in Shanghai and the other in Dalian.

The Liaoning, a carrier bought from Ukraine in 1998 and refitted in China, has taken part in military exercises, including in the disputed South China Sea, but is not yet fully operational.

Successfully operating the Liaoning is the first step in what some military experts believe will be the deployment of Chinese-built carriers by 2020.