Pakistan had asked China to provide sea-based nuclear second-strike capabilities in exchange for permitting China to convert the deep-water port at Gwadar into a permanent Chinese military facility, a longstanding ambition by Beijing.
According to a report by US-based independent news outlet Drop Site News, the demand was said to have been made in 2024 in bilateral negotiations between the Pakistan military, headed by Field Marhsall Asim Munir, and China.
In exchange for giving a military site, Pakistan handed over to China a list of its demands, including indemnification against US retaliation, modernisation assistance to match the capabilities of India and nuclear second-strike.
China, reportedly, refused to entertain the demand as it concluded that fulfilling the second-strike request would amount to Beijing's direct contribution to nuclear proliferation in South Asia.
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Beijing had termed the demands unreasonable as it would compromise Chinese non-proliferation commitment and invite international consequences disproportionate to the strategic value of the Gwadar base.
What is sea-based nuclear second-strike capability?
A sea-based nuclear second-strike capability refers to a country's ability to launch retaliatory strikes from hidden, nuclear-powered submarines (SSBNs) after suffering a devastating first attack.
It is considered the most survivable leg of a country's three nuclear fronts - land, air and sea - as land-based missile launch sites and airbases are stationary and are more vulnerable.
On the contrary, SSBNs move constantly and remain hidden deep underwater, hence making them almost impossible to detect or target.
How many nations have a second-strike capability?
Only six countries hold sea-based nuclear second-strike capability. The US, Russia, China, France, the UK and India have the ability to operate sea-based nuclear strikes from nuclear-powered ballistic submarines.
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While the US maintains a large, highly sophisticated fleet of Ohio-class vessels, Russia has a modern Borei-class submarine to patrol the Arctic and Pacific.
China has Type 094 submarines equipped with long-range ballistic missiles. India achieved the feat through the domestic Arihant-class program, which continues to expand to ensure a continuous deterrence rotation.