The commissioning of the Chinese-built Hangor-class attack submarines will substantially improve the Pakistan Navy's combat and deterrence capabilities, according to military affairs observers.

Wu Peixin, an observer in Beijing, said that the deployment of the Hangor-class submarines marks a strategically significant hardware upgrade in the history of the Pakistan Navy.

"As the first submarines in South Asia fitted with an air-independent propulsion system, they are equipped with China's domestically developed Stirling engine, and this means they can navigate silently at certain speeds for several days. Such capability delivers a generational leap in performance compared with conventional diesel-electric submarines without AIP systems, and to some extent, enables them to engage with nuclear submarines," he said.

On Thursday, the commissioning ceremony for the first Hangor-class submarine, PNS/M Hangor, was held in the Chinese coastal city of Sanya in Hainan province.

Pakistani President Asif Ali Zardari, who visited China, and Chief of the Naval Staff Admiral Naveed Ashraf, the top commander of the Pakistan Navy, attended the event and made speeches.

Zardari said that the induction of the advanced submarine was a "historic milestone" in the Pakistan Navy's modernization, affirming his nation's resolve to maintain a robust, balanced and credible defence posture.

Ashraf stated that the new submarines are armed with state-of-the-art weapons, advanced sensors and an AIP system, and they will be key in preserving maritime order and stability in the region.

The new assets will bolster Pakistan's maritime defense and modernize its fleet with cutting-edge technology, the admiral added.

According to the Pakistan Navy, the commissioning of the first Hangor-class submarine "marks another chapter in the time-tested and enriching friendship between Pakistan and China".

In 2015, the Pakistani government announced that Pakistan and China had signed a deal for eight attack submarines, disclosing that the first four vessels would be built in China, and the remaining four in Pakistan.

Wu noted that each Hangor-class submarine is fitted with a cylindrical bow sonar array and multi-line flank sonar arrays on both sides of the hull, granting the boat outstanding capabilities to detect and track hostile submarines.

The observer said that in terms of weapons systems, the Chinese-built submarines can carry torpedoes and missiles made by China as well as weaponry from other countries. These weapons are capable of striking surface warships, submarines and land-based facilities, and laying naval mines.

"With eight Hangor-class submarines set to enter service gradually in the future, Pakistan will build an asymmetric maritime advantage in its region. The new assets will offset its rival's numerical and scale edge in surface vessels, help to secure the country's transportation of fuels and materials, and strengthen its strategic influence across the Indian Ocean region," Wu anticipated.

Another observer, who wished to be identified only as Xiao, said the Hangor-class submarines can operate in coordination with Chinese-built frigates in the Pakistan Navy, and that means the Pakistan Navy can use a small group of advanced assets to pin down and deter hostile naval forces.

"Thanks to the AIP system and other modern silencing technologies, the submarine features outstanding acoustic stealth performance. It can team up with surface warships to strike enemy vessels and land targets at long ranges, wielding powerful strategic deterrence," he said.

Moreover, under the submarine project, China has transferred to Pakistan full sets of submarine design skills, construction techniques, and maintenance capacity, and has helped train a large group of workers, engineers and technicians, allowing Pakistan to break away from absolute reliance on Western suppliers and reduce the full life-cycle cost of the Hangor-class submarines, according to Xiao.