China says it's building new homegrown aircraft carrier

Beijing(CNN) China says it's building a new homegrown aircraft carrier as it seeks to expand its military clout.

Beijing already has one aircraft carrier, the Liaoning, which it bought from Ukraine in 1998, spent years refurbishing and put into service in 2012.

The new carrier was "independently designed in China" and is being constructed in the northeastern port of Dalian, Chinese Defense Ministry spokesman Yang Yujun said Thursday.

The U.S. military and independent analysts have long believed that China has been working on its own aircraft carrier project while using the Liaoning for training purposes.

"China ... continues to pursue an indigenous aircraft carrier program and could build multiple aircraft carriers over the next 15 years," the Pentagon said in its annual assessment of the Chinese military earlier this year.

South China Sea tensions

The new carrier's design and construction is "based on research and experimentation" on the Liaoning and will bring "improvements in many aspects," Yang said in a statement.

China has been ramping up its military spending to reflect its growing international influence. Naval power is of particular significance, with Beijing locked in a series of territorial disputes with regional neighbors in the East and South China Seas.

It's extensive claims in the South China Sea, where it's built artificial islands to bolster its assertions, have led to some tense encounters with American ships and planes in the region.

Ski-jump takeoffs

It's unclear whether the Liaoning is fully operational yet. In its assessment earlier this year, the Pentagon said aircraft squadrons weren't expected to embark until 2015 or later.

The new carrier will have a gross tonnage of 50,000 tons and a conventional power source, Yang said.

It is expected to carry Chinese J-15 fighter jets and other aircraft, he said. Fixed-wing planes will be able to perform ski-jump takeoffs.

The Defense Ministry promised to continue to provide updates on the carrier's progress.

'The path of peaceful development'

But it's likely be a long time before the Chinese People's Liberation Army is able to match the naval capabilities of the U.S. military, which has 10 aircraft carriers in service and two under construction.

In the Defense Ministry statement, Yang reiterated that China will stick to "the path of peaceful development" and "a national defense policy that is defensive in nature."

"We have a long coastline and vast sea areas under our jurisdiction," he said. "It is a sacred duty of the Chinese armed forces to safeguard maritime security, sovereignty over territorial seas and the maritime rights of the country."

But some of China's neighbors vigorously dispute how far Beijing's sovereignty extends across the waves.